Here is my first Karis review after using it for 2-3 weeks and playing some of my best TT with it.
This is a solid rubber - I don't think a huge Tenergy rubber fan will like it, and I am not sure how well it compares to Airoc Astro M and S, which I suspect are closely related. In fact, when I read the reviews of Astro M and S, I laughed because the way I felt about the M spinning better than the M+ in some ways which many people seem to find for the Airoc saying the S is better than the M.
The topsheet is harder than the usual rubbers, make it less bouncy and great for pushing. The rubber is extremely direct and precise - you can pretty much aim the ball exactly where you want it to go and control the arc. I think some people who like aspects of OVA or similar hard sponged rubbers will like both the M and M+. There is good but not strong catapult but the balance fits my game very well as I like to take good swings at the ball.
The topsheet grip is excellent - similar to the OVA and Tenergies with little slippage. The arc is lower than modern rubbers but easier to control. People who like to play with extreme brush will actually like this rubber as the feeling of brush is what it is designed to support. It doesn't have the easy spin of Tenergy but the spin you get is definitely what you asked for and the way from the table looping is pretty precise. It takes some practice to get some of the arcs that you might be used to from high throw rubbers, but you can get them, you just have to create them. IT reminds me of Joola Rhyzm (the original) or Tibhar Aurus.
Again, since I have major short game and over the table issues with Tenergy, this has been a major improvement for me. I don't think this will be true for everyone. Also, people who have used Airoc Astro may not find much of a difference, but I have. I have had great results playing with both the M and the M+, better results with the M, but still great results with both. If you are someone who used a slower blade because you hated the bounciness of Tenergy, this could have you using a faster blade again (I have gone back to true OFF-/OFF blades as my short game and blocking have improved with this rubber).
The M is ighter and I don't think you are missing much if you pick it over the M+, but that is just me. I use both interchangeably without losing sleep, putting the M+ on my lighter blades and the M on my heavier blades.
The rubber is only $50 from Nexyusa.com. Feel free to give it a try and if control issues are what holds you back, definitely look into this. I do get heavy spin with it (no one has told me recently that my spin game has suffered - one of my practice partners said that initially because of the lower arc but he still blocks my loops off the table.)
REcommended for loopers who like the feeling of hard topsheets and precise control.