http://www.rf-onlinegame.com/index.phpRF Online went F2P about a week ago. I used to play it for a bit in beta; besides the grind (its a fuk asian mmo after all

)it wasn't a bad game. The PvP is well developed and somewhat balanced, and the Chip Wars that happen 3 times a day can be pretty fun. It's PK-anywhere, but all you'll lose from getting killed is the time it takes to travel back to where you were.
Personally, I like PK-everywhere cause it strengthens ties with levelling/PK parties and guilds. Nothing beats an uber-teamup to beat the crap out of people. It's definitely not for everyone, though.
There are 3 factions fighting it out, the Accretians, Cora, and Bellato. The Accretians are robots that have great defensive and pretty good offensive ratings, but no force (magic) powers. They cannot be the Spiritualist class. The Cora have the strongest force powers in the game, but are the weakest in defense. The Bellato are well-balanced midgets who can't quite match the destructive force of the other races, but the balance they have allows them to hold their own against any of them.
The "unique" classes of every faction can be fun, I hear. Accretians have Launchers who are essentially gunners with massive damage output but slow speed, Cora have Summoners who summon one of a few entities to fight or support alongside them (duh), and Bellato have Drivers, who can pilot machines that deal a lot of damage and have great defense ratings as well.
I'm giving it another go once the servers empty out a bit. I've been looking for a decent PvP-based F2P MMORPG for a while. I've heard both good and bad things about this particular game, so I'd like to see it for myself.