I managed to pick up a copy of Planetside, and I'm happy to say that I've had a ripping fun time. With a band of friends, and a serious case of need to whoop ass, I logged on and proceeded to slaughter. It takes a little getting used to, but any fan of Massively Multiplayer games should have a good time with this one. Given that it's player vs. player all the way, get used to having a tough enemy to crack, and one that learns well to boot.
Based on a series of continents, reachable by an orbital shuttle that launches every 10 minutes or so, warpgates that transport you instantaneously from continent to continent, or a respawn technology that double-functions as a teleporter, this game is absolutely massive. The game is playable right out of the gate, and you technically don't need to go up in ranks to get much in the way of special equipment, but the extra ranks do help you in carrying a variety of your favorite toys from battle to battle. Vehicles abound'buggys, tanks, fighters, and even dropships, but sadly, no watercraft. Don't worry; there isn't much tactical use in water anyway.
As any MMO game is want to do, it isn't yet perfectly balanced. There have already been a variety of issues cropping up regarding experience gains, and some discussion about one of the factions being significantly weaker offensively, perhaps dramatically so. As a great bonus, the game features a strong emphasis on grouping together in squads, and larger outfits. Squad Leaders can earn command XP, which increases their command rank, conferring a variety of unique abilities.
Still, I've been playing it since launch, and even when the game gets stymied by some bad gameplay, I enjoy myself. The strength of the game lies in the squadding, and the still heavily social environment, even though you're dedicated to killing people left and right. With a few more tweaks, I think Planetside will be a fine example of MMO gameplay.