I've been playing through all of the 'Tales' games (at least the ones which are available in English) since I bought bought Tales of Symphonia (great game), and Tales of Legendia is definitely one of the weaker titles in the series - but it isn't necessarily a bad game.
The first part of the game (main story) is pretty standard fare RPG-wise, the second part (character quest) was a bit dull (and had no voiceovers), and the gameplay consists mostly of button mashing.
The game's strengths are character development and comedy (it's certainly one of the funnier 'Tales' games), it's also very well voice acted (1st half) and doesn't suffer from the agonizing load times that plagued Tales of the Abyss.
Overall it's an O.K. game, but unless you're a big 'Tales' fan I'd avoid it unless you can get it on the cheap.