I've tried the 1 star version of these balls. I have mixed feelings about the ball. I've tested the ball during a half hour against a flat hitting player with SP on the backhand, my level (+-2100-2200 USATT).

The ball has a very nice bounce and for defenders the ball doesn't stop in the air (like the 40+ Chinese garbage did). However, I felt the spin was clearly less than with the seamless XSF 3* balls we usually use. We played with the latter one, using the same drill, after the DHS ball broke to have a comparison. The ball might behave different with a spinny player, it might be the ball wasn't good from the beginning because it broke or we might get more spin out of it by adapting.

Speedwise I found it a bit faster than seamless, but you adapt quickly. I also found it more direct in feeling and flight trajectory. The ball is also broken white.

So nice bounce, a bit quicker, but my biggest con is the lack of spin.

Try the real ball. If you like the Nittaku ball, there is really nothing to discuss. If you don't then it is the same old stuff.

The real ball being the 3* one? Why would there be a difference in playing characteristics between 1* and 3*?

I've tried a Nittaku Premium ball briefly and wasn't a big fan of it (again lack of spin compared to seamless against the same player).

The one star ball came out earlier in the development process.

Personally, if you don't like the Nittaku ball, I can't do anything more as the sport needs a consistent and durable ball and this D40+ is a step in the right direction. as was the Nittaku. The old 40+ deformed too easily and what people were calling spin was really a deformed ball doing things it wasn't supposed to do and bouncing so low you could not do anything with it.

I've ordered 72 from TTNPP (who I swore I'd never order from again!) so hopefully will be able to give an opinion on the D40+ in a few weeks. $40 for 72, worth a try.

Some thoughts from a modern defender chopping on backhand and fishing or looping on forehand.

Received the D40+ from ttnpp about a week ago and have tested it 4-5 hours.

Disclaimers:
Without being able to measure the rotation of the balls its hard to tell if the feeling of less spin is caused by less rotation or other factors. Therefore I'll be using the term "spin effect" to describe how the balls compare spin wise.

Here are my ratings:

Bounce
1) NP / D40+: Nice even/predictable bounce.
2) Hand selected Chinese seamed (roundness/hardness tested by players). Low bounce is good for me as long as its fairly even.
3) Seamless / G40+. Bounces too high in my opinion.
4) Regular (poor) quality chinese seamed. Uneven bounce lowers quality of play.

Spin effect (more is better for me)
1) Chinese seamed
2) NP / D40+ / Seamless. Feels about the same.
3) G40+. Horrible! One of the better junior players ripped all my chops. Players start backhand looping chops.

My results in match play
1) Chinese seamed
2) NP / D40+
3) G40+

Durability (haven't tested D40 long enough yet, but none broken so far)
1) G40+ / Seamless: G40 Lasts long but becomes dented. Seamless last long but can break on edge hits.
2) NP: Last long, but turns blank and loses color.
3) Chinese seamed: Poor overall. But variable quality so some may last a while.

Cost of 3*
1) D40+ / Seamless
2) G40+ / Chinese seamed
3) NP

Overall
1) NP / D40+
2) Hand selected Chinese seamed (roundness tested and even hardness)
3) Seamless
4) Regular quality Chinese seamed
5) G40+

In general I think the NP / D40+ improves quality of both training and match play. A bit more spin and it would be perfect.