Gerard Butler as the scumbag cop was great. Pablo Schriver (who I'd only ever seen in "The Wire" before) was great as the villain. I didn't really like the guy who played Donnie on my first watch, but warmed up to him afterwards. 50-Cent was really good stunt casting.
I think they could have upped their game a little with the casting of some of Butler's crew, but overall really good job considering how nobody outside of Butler was really a "big name" actor.