Well space mission is a whole new ballgame, but not too hard when you used to it. It is also nice to change the space controls to suit your needs, like disable reverse mouse, and change the "roll" buttons to your A and D.
Polis Massa is a bit annoying, in the way where stupid teammates are always blocking your path. I won't call it hard though, just annoying. FF off helps alot here. (then again I don't really like to play FF off, I get more kills off my team than comp most of the times)