You will definitely get your money's worth from this addictive Puzzle-RPG. A short breakdown.
The Good:
Gameplay - The game's battle system is amazing. Simple yet multifaceted. No two battles are ever the same during the campaign. The mechanics are just fantastic. You will find yourself, even after 20+ hours, still trying to hone your linking/fusing/combo skills into the wee morning hours.
Difficulty - This is another thing they nailed right on the head. The AI is no slouch. Sometimes, you will feel invincible...only to find your next opponent wipes the floor with you. The game requires both strategy and tactics through every part of the campaign. Throw in some unique and difficult boss battles, and you may find yourself sweating a little.
Content - Units. Artifacts. Hero Spells. The content and customization in this game far exceeded my expectations. Throw in unlockables, competitive multiplayer, quick AI battles, and leaderboards. This game is a terrific value at the XBLA price.
The 'meh':
Story - It's not overly engaging. Not terrible. Easily forgettable. It's because of the story that the campaign pacing feels a bit rigid.
The bad:
Nothing I can think of. I even enjoyed the unique cartoon graphics (It is a DS port).
All around, a diamond in the rough. I love being pleasantly surprised by games like this.