I have had this mouse for almost 2 years and it is the best mouse I have ever had. It is very comfortable to use and it did not disappoint me at all in terms of handling and gaming performance.

The negatives: After all this time, I noticed that the charging base started to have connection issues. Most of the time, when I tried to charge it, it wouldn't charge on the first try. Eventually, it completely stopped working and I had to send it for repairs. After they fixed it, it started to not work properly again...not completely, but still. I thought to myself that I didn't want to go through the hassle of sending it back again, but the tragic part is that the store I bought it from told me I had to pay for the shipping to send it and receive it back. Anyway, I'll skip that part...Then the USB stick stopped working and I had to replace it, which again required me to pay for the shipping, but this time they covered the return shipping...That's something. I believe that for a mouse that costs 96 euros and is meant for professional gaming, such issues should not occur, especially since I did not mishandle it at all. Supposedly, these are designed to withstand "abuse"...But with not so demanding use, it had such damages

For a mouse that Razer sells for 170€ and Skroutz for 80-90, it is the best you can buy for that money! Very lightweight (although at first I thought it was fake or would break with use, but it turns out it's quite convenient), comfortable in the hand, no need to deal with batteries, and nice RGB on both the charging base and the mouse. I don't play FPS or MOBA or MMO games, so I don't have a particular opinion on the movements, and it doesn't have many side buttons, but it suits me well for casual offline gaming and I've had it for 6 months now. The battery lasts for more than a week, but I use it for about 3-4 hours on weekdays and around 15-20 hours in total on weekends. It charges quite quickly, even with the cable, so there's nothing negative here. The only negative thing I find (or my mistake in Razer Synapse) is that when the PC shuts down or goes into Rest mode, the mouse's RGB continues to light up for about 10-15 minutes. And secondly, the charging base has not turned on 2-3 times and I had to unplug and plug it back in. Overall, I recommend it and it hasn't given me any other problems so far, and I'm considering buying it in white for my new build.

I have been using this mouse for 3-4 months now. It hasn't caused any issues.

Let's start with the positives:

1) Classic Razer quality, which means durability and reliability.
2) Very fast mouse, especially on the day I am writing this review (27/8/2022), its price is at €78.00, which is a very good price considering I bought it for around €120-€130.
3) It fits my hand perfectly, as I don't have a particularly large hand. However, it might not be as comfortable for people with larger hands.
4) The synapse works perfectly with the mouse.

Now let's move on to the negatives.
1) The mouse has a flaw in the part where the Razer logo lights up. If it falls, it will scratch. I don't think this is just my problem, as other people who have this mouse have faced the same issue. Apart from this, which is annoying and should be fixed by Razer, there are no other major issues.
2) Now a bigger issue for me. The click intensity. What I mean is that while it is easy to click, the problem is that at night when I am using my membrane keyboard for work, it makes less noise than the mouse. Overall, I would prefer it to not make as much noise.

Overall, the mouse is perfect as I mentioned before, but the only thing that bothers me is the noise the buttons make. Again, this is my personal opinion, but the issue with the plate is definitely something that Razer hasn't paid enough attention to. Maybe because it's not exactly plastic, but a different surface.

Bought it on Black Friday for 70 euros.
For the price I got it with the charging dock, I would say it has no competition.

It has good mouse skates/feets for smooth gliding even on cheap mouse pads.

Good battery life.

Fast charging, especially with the cable.

Relatively comfortable grip for both claw and palm grip.

Responsive and stable/jiggle is good, making it a good mouse for FPS games.

Lightweight.

The only negative thing I consider is the Razer Synapse that I don't use, it sometimes creates strange problems like blue screen and occasionally downloads and uploads, causing lag when I play games with my slow connection. I only used it once to disable the right side buttons because I accidentally pressed them since the mouse is for right and left hands and has side buttons on both sides.

Update: I'm giving it 1 star less because the charging dock doesn't hold well anymore and you have to try to position it correctly, which becomes annoying. The side where I place my thumb has a worn rubber surface. Occasionally, after a long period of inactivity, it may not respond and you just need to turn it off and on again.

These are minor issues I mentioned, but if you don't buy it when it's on sale, the price is steep.

Update-2 2024: If you look at the photo, the mouse on the sides with the rubber surface has worn out in the center. This started within the first year. Besides that, the battery life barely lasts a full day and the scroll wheel loses grip during rotation, and this is not due to heavy use because I use my Logitech mouse as a backup. Charging with the dock requires multiple attempts to make it connect.

In short, it's cheaply made, I definitely don't recommend it for claw grip users as it is low on the top and the rubber side where the thumb rests will wear out quickly.

For the price they ask, it's not worth it even at 50 euros, mainly because of the sensor. But if you don't care about RGB and related features, there are similar and better mice on the market for a lower price.
I give it 3 stars for the issues I mentioned and the initial price.

The purchase was made on 18 Feb 2020 and I have been using it until today. The mouse was fantastic at the beginning of the first few months of the purchase, the best thing I have bought so far, but I have encountered many problems since then.

For example, the side buttons do not work consistently. It doesn't work at all for 3 days, then it works for 1 hour the next day, and then nothing again.

Many times it doesn't turn on, and I have to manually close the mouse, unplug the USB for wireless use, open the mouse, and then connect the USB to be able to use it.

Now it has started to not even work with the cable, and it doesn't give me a notification to know when the battery is running out or if it is fully charged, even though I have uninstalled and reinstalled Synapse multiple times!

The material on the side of the mouse for grip wears out easily due to frequent use.

In the end, I bought the Hyper X Pulsefire wireless for 45 euros, which doesn't have software to mess around with. You charge it once and it lasts for days, and you forget to charge it. But I will also write a review for it after using it for a year or two

I will speak honestly. This specific mouse did not satisfy me. I come from a Logitech mouse (G403) which is obviously heavier, half the price, wired, and I used it for 3 whole years with many hours of use.

This specific mouse did not suit me in terms of feeling (smooth movements, to put it differently) and shape, as it is designed for both right-handed and left-handed users. It is quite small, so even I, with a medium-sized palm, struggle to hold it comfortably, even after 3 months of use.

I consider it overly expensive for what it offers. Consider that by switching from the G403 to this one, I felt like I was going from a mouse made of high-quality material to a fake one. Up until today, I emphasize, neither the grip nor the feeling of moving the mouse satisfied me. It feels like it's rubbing on the mousepad, causing issues when moving the mouse in all directions.

Finally, I was quite skeptical about changing mouse brands, but now from personal experience, I can say that if you have to choose between Logitech and Razer... it's better to choose the former.

My opinion is purely subjective and based on my personal experience. Other users, obviously, may have gotten used to and been satisfied with the product.

P.S. 1: The mouse never presented double-click issues that have been reported for other wireless mice. In this aspect, it works flawlessly.

P.S. 2: (2023) The base of the mouse had charging problems from day one, and you could never charge it properly, only with the cable. So, in short, it's a waste.

Personally, I don't plan on trusting Razer with mice again.

Over the past year, I have been using this mouse almost constantly, with occasional changes to try out other mice, but I always end up coming back to this one.
I have seen many truly amazing mice come out on the market, and I own several of them.

Unlike in the past, the market is now a continuous battle of innovation for all companies (I'm not talking about you, Corsair). It is very difficult to stand out anymore.

In the last 2 or maybe 3 years, Razer has made a complete 360-degree turn with their products (not all of them, of course), offering true innovation in their category and bringing features that were once only for enthusiasts to the mainstream market.

For a while, the popular Logitech G Pro Wireless was at the top of the wireless mouse category. Even with Logitech's latest entry (G PRO X Superlight), the Razer Viper Ultimate continues to offer more at a lower cost. I will compare them later.

The Viper Ultimate comes with a brand new sensor without any issues with acceleration, spin-off, compatibility problems with mousepads, and adjustable lift-off distance. It also has optical switches, avoiding double-click issues while having the lowest latency and a battery life of 70 hours. It weighs only 74 grams, has 100% PTFE mouse feet (I will explain more later), and even has a Speedflex (like Paracord) charging cable so you don't have any resistance during your gaming session when you need to continue playing while charging the mouse. Finally, it comes with a charging dock, which is incredibly positive in my opinion because besides solving your problem, it looks beautiful and stylish while charging.
Razer definitely did not compromise, so it's no surprise that many people are excited about this product. The only issue most people face is that after a few months, the dock doesn't charge the mouse right away and you have to take it out/put it back, shake it, etc. If you are experiencing this issue, try cleaning the contacts with a damp cloth, that's what fixed mine and from what I've seen, it has worked for many others on the internet as well.

If I were to change anything about this mouse, it would be to have the Razer Deathadder V2 Pro's clicks, which are the second-generation optical switches. Functionally, nothing changes, I just prefer how they sound.

The wireless technology in this mouse is very fast, and personally, as even "Pro Players" have mentioned, I don't feel like I'm playing wirelessly. The times when wireless mice were inferior to wired ones are now a thing of the past.

If you have the Razer Viper or Razer Viper 8K and want to switch to the Ultimate because you like the shape and want wireless, just get a Bungee (like the Razer Bungee). Does it make it wireless? No... but it makes it feel like wireless! You don't lose much freedom from wireless, but you gain a lot compared to before.
The mouse is also ambidextrous, with buttons on both sides. Don't see it as a negative that you might make missclicks, it's not in a position where your fingers rest. Of course, you can always disable the buttons that you will never use. If your hand is medium-sized, the mouse will suit you for all grips. If it is large, Claw or Fingertip Grip (and Palm if you hold it very far forward). If your hand is small, perhaps the Razer Viper Mini is the solution for you (and it's MUCH cheaper).

The Mousefeet are among the best on the market. Most mice that claim to have "100% PTFE" feet are usually very thin and instead of gliding, they scratch the mousepad. I decided to try the Tiger Arc 2 Mousefeet for my Viper and I can say that I don't notice a significant difference. However, on other mice like the G Pro Wireless, there was a huge difference. (the difference is due to the very poor feet of the G Pro)

BUT at first, the feet of the Viper were not as smooth, but after a day or two of use, they were perfect. I guess they need some use to wear down a bit? I don't know the details. So if you just get the mouse, it's not exactly what you wanted, give it a little time.

Something I don't know how to answer is how durable the mouse is. One year later, I haven't experienced any cracking or creaking sounds in the plastic, it doesn't feel fragile, and it hasn't broken. So I assume it's durable? I generally don't abuse the mouse :P

The price, considering the market, is not excessive, especially now. When it was released, it was priced at €180, which obviously I don't see a reason to spend that much money, but now it has changed quite a bit. It is definitely much more expensive than a wired mouse, but in order for a product to become even 1% more advanced than its competition, it costs a lot in research and development. So maybe it's reasonable? So it's questionable if it's worth the money, but definitely not something you throw away. It is an excellent product, just like the G PRO X Superlight, you pay extra for something that sets it apart from the market. So the buyer will judge if they prefer the Wireless over the Wired for the extra money.
The only "cheap" and well-known wireless mouse is the Glorious Model O Wireless, which over time, Reddit has been filled with reports of problems that often were not resolved or consumers didn't want to go through the process of contacting their infamous support. Is it worth the risk to save some money? I don't know.

If someone is torn between the G Pro X Superlight and this one, personally I would choose the Viper Ultimate. The almost glossy plastic of the G Pro X makes my hand sweat, the clicks don't have a smooth sound across the entire surface, and many times I hear something like a "double click" on the Click switch (it doesn't translate to Double Click on the PC, but there is a delay in its response, so when I need to spam clicks depending on where I have my finger, it becomes an issue). The charging cable is terrible and makes it difficult to use the mouse while charging, and finally, in the past, the G Pro, like many Logitech mice, was known for having a Double Clicking problem.
Apart from that, it is a good mouse. Excellent wireless, excellent sensor, without any significant issues during use. I wish it came with a base...

Lastly, when purchasing from stores with the "Authorized Reseller" badge, you are covered by a 2-year warranty from the official Greek distributor, and even after the warranty period, there is support and service to assist you. I mention this because it might be a selling point for some.