The only one I've played was Planetside. It was okay, but since it's *all* PVP, you are frequently competing against a lot of people who have every ability in the game (including those friggin' indestructible giant mechs they added in the expansion), and it can be tough to find people who will work together well unless you join an organized guild. I found it a frustrating game to get into.
I don't understand your question, though. It's like a simplified version of something like BF2, but with several hundred players in one (very large) area instead of just 32 or 64 in a significantly smaller one.