Those big battles in Planetside 2 are always fun, especially considering how important staying alive and protecting one's spawn/sunderer (spawn truck) is. Really adds a strategic element making each hill/tree/ditch/etc. invaluable and worth fighting over.
2000 players per server, and there's like 5 servers ;p
Briggs > Graveyard (to say)
Cobalt > Fair or something.
Connery > Quite good, the melting pot, except less red faction and more spandex (I play TR here, and only play here).
Emerald > MLG/420BlazeIt/Swag
Jaeger > Who?
Miller > Lite
I felt I should explain the 5 servers at time and their status.