Might come a bit late, but since I don't live in Japan (yet? lol) and had to wait extra-long for my Nintendo DS + Pokémon Dash because I also wanted to get the Japanese 7th Movie DVD which came out on December 21st, I only got the game a few days ago.

So, umm, donno' if anyone's still interested in this, but here are my impressions:
http://filb.greenchu.de/games/dash.php

I'm sorry for not being multilingual with my site
Maybe a basic Babelfish translation might help?

I also put some of the in-game music on my site (in order to save webspace it's not in optimal quality, though).