Installed this last night. I don't recommend it unless you really want one of the features. I mean REALLY want. Installing was painless, but in order to get album art and most of the color themes, you have to download the source code, apply patches, and compile it. No thanks.
The interface is really tough to handle. I have to hold down play for 2 seconds (but not 4 seconds!) while playing a song to get back to the file list. I have TagCache going but can't for the life of me figure out how to add songs to a playlist when in tagcache mode. Or any mode really.
There appears to be no way short of resetting the iPod to get back to the root level of file browsing.
AAC playback is utterly horrific. As I feared no DRM enabled AAC files even show up. And regular AAC skips, resets, and just does not play at all really.
I like the equalizer, it may in fact be a little TOO good, because I don't really understand all the settings.
I'd recommend waiting until at least 3.0... the thing is buggy, eats battery life like you would not believe (my estimate is 4-5 hours of use, if you are really lucky).
If you do try it, I recommend using the firmware that makes the apple OS the default and only when you hold down menu when booting will rockbox load.