Since Final Fantasy Tactics, I haven't seen another SRPG worth playing. I'm glad to be proven wrong.
Gameplay: The gameplay is a more lenient version of Final Fantasy Tactics (FFT), if you've ever played that, in the sense that you aren't required to assess the distance of attacks before you move. If you make a mistake, you can simply undo an action and re-input commands. Players may utilize up to ten units to defeat enemies and collect items. You start the game out with some units, many of which will become obsolete rather quickly. I personally recommend creating a mage, I went with a Blue Skull, other than the Red Mage you start with. Also, make a Heretic to replace the Healer you're given. Heretics can actually fight back, in addition to healing and buffing. The sense of humor really keeps the game moving along, even at the more subtle moments. For the most in depth gameplay info, watch a gameplay video.
Audio: Disgaea 3 has a great soundtrack. In addition to some past tracks, they've added some original ones (as to be expected). If you're a fan of Japanese music, and the fact that you're playing Disgaea insinuates that you are, you'll enjoy the opening especially. The music always suits the situation, regardless of how serious that may be. The sound effects are particularly run-of-the-mill, however, not that that matters really. As with most of the rest of the game, the best way to experience everything is to play the game, and if you're a fan of RPG's, you should be all means buy this game.
Graphics: I'll say this once, GRAPHICS ARE THE LEAST IMPORTANT ASPECT OF ANY GAME!!! Regardless from the fact that this game has PS2, possibly even low-end PS2 sprites, I promise that that won't take away from the fun.
Overall: If you're a fan of RPG's, and/ or have even the slightest sense of humor, you'll most likely enjoy Disgaea 3. Not that anyone will actually read this, but there's my review of Disgaea 3.