BF2 is a better game, from my Beta impressions. However, 2142 is still very good, and its new. Yes, some games may be the best in the world, but you can only play a game for so long before it gets boring. I've played BF2/SF for 250 hours and I've had about enough. I only play Jalalabad and POE now, as they're new.
POE 2 is sort of like SF is to BF2, a very similar game with differences. Like SF, its about equal to BF2 in funness.
A number of things bring down 2142. Automatic weapons such as the enforcer and accipiter drone. Drop pods which render battlefields rather pointless as people just hop everywhere. Overbalancing as well, there used to be a difference between playing factions, now they are almost carbon copies of each other. Hopefully Conquest will be better.