I decided to play some conquest in Vietnam today and surprisingly found it far more enjoyable than rush. In regular BC2 I always play rush, but the maps in Vietnam seem to be much better suited to conquest. Also, the shotgun is beastly, I decided to use it just to work towards getting the silver/gold stars and found it to be extremely effective. I'll probably use it quite a bit from now on.
Shotgun + Slugs + Mag Ammo + headshots = Everyone you kill calling you a hacker.
I love the 870 shotgun, , its a toss up between that and the flamethrower for the best "Screw this, I'm just going to pretend to be a badass for the rest of the game" weapon.