I have it. A 7 at best.

Pros:
Address book is in VCF format (universal format: outlook, palm software, even handphones use these)
built in mp3/midi player
Directory browser

Cons:
The interface is a bit bleh. in order to delete files, you have to select a sub swap menus and then delete.
Touchpad interface is kinda wonky. it feels uncalibrated, the pointer keeps flying all over the screen.
The paint program hangs my DS when I tryied to save it. (I'll stick to Draw3 (better homebrew paint prog))