Just another cheap opinion but...
I just couldn't really get pulled into this one. The last 5 - 10 minutes were okay (after they broke out of the arena) but the rest didn't do it for me. I didn't find the heavy all that intriguing and I could really see no reason why her number one (Junner, I think) wouldn't just off her and collect the extremely high bounties on all the cryo-frozen criminals. Also, I think I didn't like their take on the mercs. In the films Johns and, to a lesser extent, Toombs were decent adversaries of Riddick, but the mercs in this film were made out to be little more than untrained thugs. It sort of took some of the mystique out of it for me, given that despite Johns' flaws he could handle himself well and Riddick was wary of him at all times.
Maybe I'm just unhappy that the Riddick saga seems to have died a Hollywood death, since I enjoyed both films. Hopefully video games will keep it alive.
Fear is the Mind Killer