PlanetSide is a fun game when it doesn't lag. If you have hours to waste for loading time than you will love it. The actual fighting is pretty straight foreward - snipers get a ton of kills. Also, the different races are unfair. The terrens (red guys) have really fast shooting stuff, the new conglomerate (blue dudes) have really powerfull weapons and the vanu soveraignty (purple) just plain suck all around.

This game is very good in concept and creates a realistic environment for multiplayer combat with a wide variety of weapons, vehicles and accessories to use. The graphics are not great but are good enough. There are always plenty of players both friendly and enemy to keep the game interesting. The 12.99 monthly fee is acceptable though on the high side.
The biggest drawback of this game is various bugs that are present from time to time.
Lag is also sometimes a annoyance.
You need quite a powerful computer to play this game. Most people seem to agree that a top notch graphics card along with plenty of RAM (1 gigabyte is recommended)is necessary to play this game. An expansion pack is also available allowing you to play in underground caves with a couple of new weapons. The price of this expansion pack is high and not worth it though.