Disgaea 3 is just one massive wacky fun ride with a caste of insane demon characters in a demon school with the core hero Mao wanting to overthrow his dad for destroying his video game system (seriously!).
This game has got seriously deep gameplay that'll keep you interested for a long time, 40 hours core story to play through before hitting end game where you'll learn more about Class World, Item World, Pirate runs and Leveling up to 9999 (if you so wish). There is simply alot todo and will keep any SRPG fans going for along time.
Graphically the game keeps to its roots with 2d sprite billboard rendered characters on simple 3d block based environment. Although not really using the ps3's cpu and gpu power, it uses its memory by having larger and higher maps then Disgaea 1/2 had on the ps2 and also by pretty much loading all of the game's assets at start up to ensure you don't have to deal with loading while you play.
The only real downside I found was the manual (esp the manual) and the in-game help is lacking. Stats aren't properly explained so you really need to figure out how they work, how much damage X amount of ATK gives etc. Geocube stacking is somewhat explained but I found I had to playaround for 30 minutes to get use to it.
if you like wacky characters, SRPGs or you're a disgaea fan already. Buy the game, you'll enjoy it.
(NOTE: story is standalone from Disgaea 1/2, hence disgaea 3 is accessable by SRPG fans that haven't played the 2 former titles).