Agreed, unfortunately their control of the software (itunes) allows them to provide many features and a ease of use that comes with complete integration that EDIG will never be able to match.
Also, I think the platform they have chosen lets them add a lot of small, useful features (games, to do lists, alarm, note taking, etc.) that while nothing fancy make the ipod a more full featured product than a simple music player.
I'm interested as to what kind of DRM scheme is involved to prevent the transfer of bought music between computers.