GF has really outdone themselves with the game's soundtrack.
The overworld themes (routes and cities) are amazingly beautiful. I also love the variety of styles and arrangements. The battle themes on the other hand, are not as impressive as I thought it should be, but still great nonetheless. The rip of the tracks posted on Youtube doesn't have the best quality (too much treble, and lacks bass) so I'd wait for the whole soundtrack before I make more judgments.
Overall, this game, so far, has the most beautiful overworld themes in any Pokemon game. I still prefer B2W2 in terms of Battle themes. And I'm actually impressed with the bike theme.