This was my 2nd attempt to finish it. I lost interest in it the first time (got about 35 hrs into it). I just don't like how you end up getting zero experience from most of the battles as you progress. I almost 100%ed it, but I don't feel like hunting down that last Star Piece. If I ever play it again, I'll just follow a walkthough so I don't miss any.
I started out liking the battle system, but over time, it just became tedious. Plenty of side quests to distract from the main quest (thank goodness for the pipes, although the one to get to Shiver City is extremely annoying). I really enjoyed the Crystal Palace.