I like the iPod Shuffle, but there are two things that are really annoying:
First, if you have your iTunes library on an external disc and connect the iPod shuffle to the computer without this disc, you are likely to get an empty music library on the shuffle (you can prevent this by deactivate the autoactivation of iTunes).
Second, I like to listen to music when I go to sleep - in the morning, the battery is neary empty. I miss some kind of timer.
...it's still a nice companion :-))