OK, here are my impressions of the G40+, specifically in reference to Nittaku Premium 40+ Japan (NP40+) and also XSF. I played with it for two hours today on Tibhar Smash 28 tables.
G40+ bounces about the same height as an XSF ball, which is a little higher than NP40+ (and a lot higher than Chinese seamed balls). Personally I like this, but if you are used to NP40+, you will need to keep this in mind.
It is hard to see the seam in a G40+ unless you shine light through it, which is also true of NP40+ (and very different from Chinese seamed balls). However, the seam in a G40+ is quite a bit bigger than a NP40+ (the amount the two halves overlap). Butterfly says that even though they have a seam, the inner diameter does not increase where the seam is. Nittaku Premium has a very very small seam.
Another
really obvious difference I can see right away with two new unused balls right out of the box is that the surface of the G40+ ball is
a lot smoother than either NP40+ or XSF. It is instantly discernible when you take two balls and rub them together. The sound of two NP40+ (or XSF) is greater than G40+ and you can feel more vibration.
As everyone mentions, G40+ has weird sound (like old seamless prototypes or Ipong practice balls), but after about 5 minutes you stop noticing or caring. Once you realize the ball bounces normally and not like a broken ball, the sound stops mattering.
The good news is that this is a perfectly decent ball and my partner and I had fun playing with it today. Also, new balls right out of the box will not put any dust residue on your rubber!! (Very different from NP40+).
Some people may consider the next thing bad news; it does not really play all that much like an NP40+, it is not really like a XSF either, and it is definitely not like a Chinese seamed ball (thank goodness). The G40+ is unique, which means that there is even more variability in the playing properties of plastic balls, and this is really a fourth class of ball. All in all it is closest to XSF I think but still has unique properties. That is the bad part. We are living in an era now with a lot more difference in ball properties than we ever had in the celluloid era. (I have seen ITTF officials try to downplay this, but it is obvious).
Dan's review mentioned that the ball flies very straight in the air. I agree, in fact it is one of the things that seems to me to be different from either NP40+ or XSF. Perhaps this has something to do with the unusually smooth surface of the G40+? I also had the impression it flies fast through the air. Is this really the case or an illusion of some type? Hard to say but that's how it seemed. If you are wondering why surface texture affects ball flight, bear in mind that (as with golf balls) a rougher texture could creates a thin turbulent boundary layer of air that clings to the ball's surface. This allows the smoothly flowing air to follow the ball's surface a little farther around the back side of the ball, thereby decreasing the size of the wake. Table tennis balls are a lot lighter, so it may be that smaller changes in surface texture are sufficient to affect blight through the air -- see
http://www.scientificamerican.com/article/how-do-dimples-in-golf-ba/).
I felt like the ball had more spin after the bounce on the table, and that it jumped less off the table as a result of spin. This could also be due to smooth surface. My guess is that it is heavier than NP40+ (I will weigh precisely next week) but also a lot harder than a XSF, so it will seem lighter when you play with it. At times it felt somewhat intermediate between XSF and NP40+ but when you flat hit the ball or blocked with authority, the ball seemed to move super fast.
My suspicion is that the very smooth surface of the ball is part of the reason it plays differently. But it is not everything. The G40+ also played a bit differently from a very well worn NP40+.
A couple of really good players on the next table (Jimmy Butler and Niraj Oak) hit with one briefly, the first impression they had was not altogether positive, but they didn't give it more than about 5 minutes. I very much value the opinion of very good players, they just see and feel things more accurately.
I am not sure if people will like G40+ better or worse than NP40+ or XSF. To be honest, I am not entirely sure myself how I feel about it.
The one thing I am sure of is that it is certainly as legitimate an effort to make a decent plastic ball as either XSF or NP40+. There were no grossly bad bounces (I am very accustomed to 40+ balls, have used them exclusively for 18 months). Didn't break one in two hours.
I will write more after I have played with it some more, and also after other people in my club at various levels have had a change to try it out. But if you held a gun to my head and say rank order the balls, I would say NP40+ > XSF = G40+ >>>>>>>> any Chinese seamed ball.
