I'm definitely in the minority with this, but I didn't find the soundtracks to either ME all that remarkable save a few themes here and there (but M4 part II was just fucking awesome); I found the first ME's soundtrack passable at best. In fact, I found the various themes in ME2 extremely inconsistent. Now, within the game itself everything's fine as things can get pretty fast paced and the music accommodated accordingly. However, once you listened to the songs outside the context of the game's events, then the songs become disconnected with themselves as the tone would shift several times over a span of 5, 6, or 7 minutes.
I'm probably one of the few eager to see what the new composer can create. Should be fun. :3