Great mod. The momentum feels good and the character reworks are great.
The Amy rework makes her a really fun character, and the Tails and Fang changes make them significantly more fun to play (and in Tails' case, easier on the hands.) I was a little down on Sonic at first but after getting more experience with SRB2 the Momentum Thok has gone from "hard to use and doesn't help much with platforming" to "totally awesome (and doesn't help much with platforming)." I haven't really noticed the Knuckles changes but I didn't play him much, haven't messed with Hyper mode but I don't really use Super or Hyper in Sonic games nowadays anyway.
My one major complaint is that the trick system feels really lame and vestigial, even before trying to use mods for recurl and the like, and while it's easy enough to turn off in the code, it'd be great if there was a console command for it.
(Well that and Blue Shoes Tails and The Secret Character showing up in randomizers and encore, but I feel like mod compatibility things aren't really a fair complaint. Also it made me laugh)