New Game + inclues a new sidequest with two crystal soldiers that awards you with an attachment when completed. You also get the white and black costume for Beryl. If you want a new dungeon you can get three of them after you finish the game and then load your old save.
I still prefer DS but there's a lot of good stuff in this version as well. The growth system in original Tales of Hearts is awesome. I like it, they should be more creative to produce something like that again in the future. ToHr growth system is just pla