I wasn't super thrilled with the Power Groove Proactive. High-RG plus dull particle surface seems kinda contradictory. Plus as a speed-dominant bowler, I had a hard time getting it to rev up well.
I don't agree with laner7pin about the Mutant, though. Great ball, smooth as silk. It was the first Track ball I had and if all their releases are like that, it's no wonder they're one of the best companies around. I know a bunch of other players around here that were (are) big fans of the Freak series.
SH