Actually I have swapped the Mantra Pro XH on my Zhou Qihao S-ALC blade with a H3N OS but have not touched my Mantra Pro M on BH side just for a test a few weeks ago. That test was so good that since I have not even touched another blade. I played a lot against SP, LP and of course normal inverted players and the Mantra Pro M is really easy to use.
Actually it is much easier to use than any rubber that I tried, Glayzer for sure is much harder to use, Tenergy is still harder to use. Mantra Pro M feels really soft, but probably on measurement it is as described @ 47deg.
But the sponge and the topsheet are so supple that I have never felt this. Like Tenergy would be the golden standard for suppleness but I think the Mantra Pros have managed to surpass it.
And it's not just soft and supple but it has good bounce, good topsheet stretch, and the grip is excellent.
In fact the sponge and topsheet support are so good that when playing against SP or LP players I need to focus more on keeping the ball not lifting too up and drifting long. I don't know but for me this "built-in" support is really nice since I can focus on placement and ball arc. I don't remember any rubber where I could "successfully and god forbid consistently" backhand!!! loop high quality balls from the floor, out of placement on to the table and still applying pressure on my opponent... Yes literally from the floor. (actually against SP)
I loved the old Mantra H for BH blocking but I love this one too, it's not particularly spin sensitive and has great speed and it eats the ball very well too, so one can kind of do adjustments during block while the rubber holds the ball. But because the sponge is so compressible it can hit down on the wood fairly easily on flat blocks, then it becomes super spin insensitive and fast. Very good rubber for just "elementary" school flat, press down block.
Kind of how like Truls does it. I know he doesn't use this rubber but it is super great for that hit and guys, it's effective.
Also I'm a lefty, and when I play against most SP players (who use SP on BH) I sometimes engage in straight BH BH flat hit rally. Normally most rubbers I have to pay attention to lift a bit or I will hit in the net since SP makes the ball just go down from my rubber. But with Mantra Pro M I don't need to worry about this and I welcome BH-BH flat exchanges. Welcoming is maybe a bit of a stretch since I'm still a bit wary of this but mostly because I have bad experience from other rubbers. I can imagine if I use it for even more I will just get great confidence and seek such exchanges.
Actively countering open up loops is also quite fun since there is the flat and push block Truls style, so that is like a swiss knife tool in the pocket always. In doubt do it!
But it's also possible to counterspin heavy open ups. It's not even difficult, just need to swing with confidence (or recklessly with closed eyes) and the rubber takes care.
For sure it doesn't have that feel when I get it right with Glayzer, since Glayzer will make it feel like I hit the best shot of the decade but Mantra Pro M will put a lot more balls on the table and possibly with greater speed, only that I don't have that epic feeling of greatness. But a point is a point so if I get more with Mantra Pro M I will take that.
Open up and chiquitas are very good too, since it has great girp and a superb sponge. I don't remember a sponge made by any other company so good. The XH sponge is also fantastic. It is durable as hell, after 2 months of use the sponge is the very same as new. Several of my teammates have killed Tenergies faster than that and I have much more power than them.
And that leades me into durability. After 2 months and possibly 100 hours of actual play the sheet has only marks where I touched it with my finger regularly (serve). Superb durablility of the topsheet and the sponge has no boosting tricks and still maintain the same characteristic as new. Clicky, speedy, supple everything is the same.
So
@igorponger is pretty correct to hype the OCS sponge from Japan. The latest one is probalby the best I have encountered.
Heck I wish Daiki will make a sticky, friction rubber like D09c with their sponge. That would be so awesome.