Lost Odyssey is probably among my favourite 360 games, and the whole seventh gen. I'm not sure I would call it the best, as there are some other games (Such as Tales of Vesperia, Demon's/Dark Souls and The Last Story) that certainly match it when it comes to JRPG greatness, but it's definitively awesome.
A quick summary of the things it does right and wrong:
+ Fun, interesting combat with a certain depth to it.
+ Some memorable characters, like Jansen.
+ Absolutely kickass OST.
+ A good story which, while having a somewhat cliche villain, manages to be interesting, with some nice twists along the way.
+ The side narrative stories of the immortals, A Thousand Years of Dreams or something like that called. They're powerful stories to find and read.
- Some useless characters that the game has the audacity to give them incredibly good skills despite being useless. (I'M LOOKING AT YOU, TOLTEN!)
- Some important story details, while not crucial, are told in such a casual, quick manner at times you'd be forgiven to gloss them over completely.
- Dungeon design is meh, for the most part.
- Balance of the game is easily broken in favour of the player, thanks to the immortals.
