I think it's a good Turn-Based Strategy game, with some nice artwork and some nice humour thrown in..But there is a lot of training involved..And you need to be careful, or you'll make a stupid mistake..But overall, it's a good game.
But if you want a TBS game for DS, go for Fire Emblem: Shadow Dragon or Advance wars (Either of the DS titles)...If you have them, and have enjoyed them, then get Disgaea.