They have good bounce and retain it, unlike pressurized balls. Especially at first, they feel different compared to pressurized balls, which is natural. However, you get used to them, it's not a problem.

They are quite durable, they last longer. I was impressed that they are not in a can but in paper packaging.

I tried them and simply didn't go back to anything else. The ones I'm using now have definitely endured over 50 hours of intense training and gameplay, the seams have shown in some of them but they still bounce normally without changing the feel too much. This makes them a tremendous value for money.

Negatives:
Due to their technology (thicker rubber walls), which gives them their characteristic durability, they are harder than the average ball. Actually, they are among the hardest balls I have encountered in the 25 years I've been playing. Therefore, they may not be suitable for players prone to injuries (especially tendonitis in the wrist and elbow).

For the few weeks and few times that I have played with these balls, it seems that they deliver on what they promise. I cannot comment on their durability, which will be evident over time, but for now, I haven't seen anything that suggests they won't hold up as they claim. The only comment I have is regarding the "feel" of the ball when it hits the racket, which I definitely feel is different and somewhat "heavier," I would say. The weight of the ball is not greater than another ball, but it is perhaps the sensation it gives me during practice.

For amateur activity, there is simply nothing better.
They bounce until the inside of the ball is visible, ... and even then they bounce like new.
The solution for training and all kinds of games outside official tournaments, etc.
You don't need to throw your money on anything else.

Good, high-quality ball with a long duration, but it is slightly inferior to the classic usopen and wilson premier (formerly auopen). It is worth trying it out to see if it suits you.