Caved in and picked it up today. I was more impressed than I expected to be...guess I had low expectations. Anyway, there's enough grass and vegetation around to make it feel like Vietnam, and that was a big concern of mine. Luckily, the atmosphere is spot on....especially the music in helicopters. However, I'd like to see more object oriented maps - more stuff like Monte Cassino from Road to Rome and such. I've noticed in this game, it's more willy nilly feeling. In BF1942, front lines tend to form at contention points - bridges, choke points in terrain, etc. In Vietnam though, it's sort of a free for all over all the landscape.
Anyway, the vehicles are cool - haven't done any piloting yet, so dont know about the choppers.
Connections have been fine...my list of gripes is shorter than good things, so here it is:
1) The server browser doesn't sort by ping. Fix please.
2) The Anti Tank American kits. M60/LAW or M79? Jesus.
3) Foliage is drawn as you approach so if you're hiding on a hill, you're clearly seen by someone more than 200 feet away. Sniper heaven I guess.
A quick performance tip - I was having FPS issues too, and when I turned off lightmaps, everything ran much smoother. Feedback welcome.
Anyway, I grade it a B- right now, but with patching that could easily make it up to a A-