I like the Vietnam maps. My first time on the map "The Battle of La Drang" I played as a medic in a squad that posted up on the south side of the map.
Our squad followed a dry riverbed and keept a lookout for any NVA trying to cross the river. The firefights got intense. About five times during the course of the map, half my squad got "incapacitated." Most of those times I was the only living medic and it gets intense when five or six other guys shouting for a medic.
Also, I played a game on another map which pitted the Russians against the Chinese. My squad was assigned to defend an oil refinery. Things were mostly calm, however about 15 minutes in a large group of enemies began shooting us from the hills that surrounded the oil refinery. One time a tank even began taking shots at us. I had to take cover behind a wall and wait for enemies to run into the permiter of the refinery before I poped them. I killed about 20 people during that match. Insanely fun.
Point is, check it out. The infantry combat is really fun and visceral. If you can, try and play some of the vietnam maps, I like them the most.