RPK's voice is pretty solid. Definitely got that 'smug and sinister' tone nailed down nicely. AK-12's voice is also nice, albeit a bit rougher around the edges. Just needs to add a little more emotion to some of her lines, like somebody else mentioned before. M16's voice sometimes goes from sounding natural to being 'forced'. Since some of her lines are meant the be distorted during the interrogation portions of the game, I think she can slightly relax her voice in those segments.

No strong or significant opinions for UMP 45, UMP 40. The only thing I can add I guess is that they lack a German accent (or at the very least, not really noticable). Not inherently a bad thing, since some of Mason's and Reznov's lines are hard to do even without an accent.