Yeah, first couple of levels for most perks is pretty easy to earn, already rank 3 as the medic. As far as multiplayer, I've played a bit more and the game is definitely better in multiplayer then solo, and I've realized I've gotten to the point of not giving a fuck about what they say, or occasionally being sarcastic(can legitimately thank hours spent in TF2 hearing 'that guys a hacker' from five year olds for the sarcasm when dealing with assholes.) Definitely going to start playing more multiplayer when I have the time.
And as far as weapons I end up carrying two med guns and usually another weapon if I can carry it, but other then that I prefer the explosive class myself.