Supposedly the cam is much-much smoother to draw,it' s about 10 fps faster on a chrono, and it has a little more vibration. I have also read it feels much lighter(although it' s not much) and is better balanced . I won' t know ' till mine gets here , whenever that is.......[:@]
As to below........I can' t speak for everyone,but I went from an MQ-1 @ 7.5" BH to an Ultra2 @ 6 1/8" BH and saw no loss in accuracy. And I' m no tournament archer , but it is probably a good idea to shoot a short BH bow at a pro-shop first .