I bought a used revo 12.9 for a great price and played with it for a few weeks. Couldn't get used to it and had zero confidence with it. Shots that I make consistently with ease with a 3142 or regular maple shaft just weren't going in with the revo. Sold it and got back to 3142 and my game is back to normal.
The revo reminds me a lot of the predator z shaft in terms of how much spin it generates on the cueball. I tried and gave up on the Z shaft several years ago just because of how sensitive it is to off-center hits. Very easy to unintentionally throw the object ball. One full tip of side spin with the revo produces way more spin and swerve on the cueball and way more throw on the object ball than a regular maple shaft or a 3142. I can go back and forth between regular maple and the 3142 with almost zero adjustment and play well. Not with the revo. The way it plays is very hard to get used to, at least for me. The only advantage I found was with extreme cut shots. I found that I could hit more fully and could count on the extreme spin to throw the object ball into the pocket. I'm glad I tried it, but much more glad to be back to a maple shaft.
Overall the revo is an interesting product and I might try another some day if they make one that, imo, spins the ball a little more naturally. Maybe the 12.4 plays a little differently, with the increased deflection you guys are talking about, but I'm not about to drop 4-5 bills to find out lol.