Engineer I like the management you have to do with him, Engineer isn't also just about kills and such, he's about the movement of the team, defense of the team, and the healing and supplying of the team.
I don't really have a favorite class. I kinda just play whatever. Normally it just depends on my mood.
spectator he can become any character and if I spectate someone rich, I can pretend I have their unusuals and aussies.