ACW-R is my favorite weapon hands down . That reload time is amazing.
I run it on engineer mostly because I've maxed out the assault class . That and an M9 or 1911 secondary
Sniper is good fun and a good challenge . ..... I just don't because I want to share the kills with everyone on my team :-P .
But seriously if you want to just relax while playing got to snipe. Even better if you can wipe out scrubs with the pistol
Conquest best game mode in the game and makes great use of the 64 players. Make sure you get into a full squad best for spawns into the action. Use Engie first and unlock carbines over all else. They are great overall and are now multi class