I finally got this game in a recent Steam sale and have been playing it with NeoGAF people. I don't have Vietnam. It seems pretty fun when you have friends, actually, though I suppose I'm only playing on newbie servers for lower ranks (I'm like rank 7?).
I've played almost exclusively recon so far to try to get all the unlocks, though I will on rare occasions go rage engineer if no one is RPGing tanks.
It seems some people here have had bad experiences at high levels or with lack of teamwork, which I suppose I can see. I have had a few games where I do REALLY badly instead of just badly, and at one point I was on a server where it was like 10 people vs 3 people (and one was afk?)...and the autobalance wasn't kicking in or something like that.
I don't mind tanks, helicopters, grenades, knives, snipers etc. so much. The main two things that really get on my nerves besides occasional constant ground-shaking (mortars everywhere?) are lack of visibility in some maps...the snow one is TERRIBLE in this regard because of snow clouds, and people could snipe us or shoot mortars from mountains through them...and people sniping with SMGs/LMGs. A sniper rifle doesn't have much of an advantage besides zoom if someone can kill me with a few SMG shots from a few hundred feet away.
In general it's pretty fun though, even though I so far tend to have the horrible habit of going lone wolf and only helping my squad through sharing vehicles, providing spawn, throwing motion mines for visibility, announcing enemy locations/scouting, and sniping. Last night I actually sniped a couple of people out of VADS or machine guns which is presumably useful.
*edit* I forgot one of the other things that struck me about the game. A game like TF2 strikes me as making it pretty easy to see everything going on around you, and people stick together. BC2 on the contrary gives me the feeling of being on a giant battlefield with the ground shaking and people all over the place, and you don't know where you're being shot at and shelled from, so you run around scared and hide in buildings and stuff. It's not necessarily BAD, just different, and feels more like a big chaotic environment.
In particular, though, I wish that there were a way to combine two squads into one megasquad, or maybe show class icons for non-squad teammates on the minimap. It feels really hard for me to coordinate with people who aren't on my squad if they're more than 10-20 feet away. It's hard enough for me to even read squadmate's names if they're running sideways past me, but at least I can try to remember who's a medic and use the icons to identify them.