I have the 30GB model of this brilliant little player.
The sound quality is good and the battery life is brilliant. It does not, however, play OGG, FLAC or SID files. It is because of this that I decided that I would like to run rockbox on it. This seemed like little more than an idea when I first looked into it, as there was only the beining of a project page open about it.
However, things have changed! It would appear that it is not too far off. There is a replacement bootloader and rockbox has been booted on one. It is not yet functional, but this is a very big step towards that.
I would liketo say a big thanks to everybody that has worked on Rockbox, not only the main application but the porting og it to various devices. It is something that, for the moment, is way more advanced than I am able to do.
I will be keeping an eye on this, I might soon be able to abandon restrictive MP3 for the open OGG Vorbis format.