I had seen many reviews before buying it, and I had initially tried a cheaper solution from iPega. I want it exclusively for emulators on my mobile. Impressions quickly:

Positives:
- Immediate response. The iPega's Bluetooth may not have had input lag as many claimed, but it suffered from tremendous release lag. This one, due to USB, is practically almost instant. I say "almost" because I'm not 100% sure. Maybe I'm still getting used to it, but the only thing I have felt absolutely immediate is the DualShock 4 via Bluetooth.
- Quality construction. It has small tolerances, no creaking, comes with a nice case, and extra pads for the analog sticks.
- Size, MUCH smaller than what you think when watching the videos on YouTube (this is also a negative, see below). However, it will be very convenient to carry it in my camera bag.
- Very good button feel. I consider it an exaggeration what they say about the noise of the L/R buttons, they don't bother me at all.
- Very, very important: my Redmi Note 10 Pro FITS comfortably with a sturdy silicone-fabric case from Dux Ducis (it could fit at least half a cm more) - and additionally, the USB connector barely fits without removing the case! I say barely because it connects as soon as the controller is closed and the phone is pressed/squeezed, not immediately when it is connected at an angle. The connection remains stable during gameplay. It was my biggest concern.
- The pass-through charging also worked perfectly. I emphasize this because not all phones are compatible, and mine was not on the list. It didn't bother me if it wasn't, but it's a welcome feature.
- For my use (emulation through RetroArch), no application is needed - it recognizes it immediately, you do a mapping of half a minute because Retroarch doesn't have a ready-made profile and maybe it doesn't automatically achieve all the mappings, and you can play everything.

Negatives:
- The small size we mentioned. The D-pad (although small), sticks (especially with the extra pads), and L/R buttons are very comfortable. However, the 4 face buttons (A/B/X/Y) are small, and things get complicated by the right stick that gets in the way when you try to press them. However, I feel that gradually my hand will get used to holding it slightly sideways and it will be okay.
- THE PRICE: it is clearly a very good gamepad, BUT it is objectively expensive. At €85 with shipping, almost double the price of a DualShock 4, it doesn't have analog triggers, vibration, that heavy sturdy feeling of quality, and the large buttons. However, it beats the cheaper competitors (e.g., iPega) by far, while the high-quality ones cost the same or more. I would have felt that a final price of €45 would be fair, or maybe €50.

We pay for the form factor - if you have it and you have extra money, at least it will do its job well.

(Edit one week and several uses later: I confirm what I wrote on the first day. Also, it is absolutely immediate. The only issue is that the left stick may have small dead zones on the diagonals. The small face buttons don't bother in most games. However, in some games like Gran Turismo, it is difficult to use them for gas/brake - there I switched them to L2/R2 like on the PS4 and the problem is solved.)