One month ago I signed up for a premium Spotify account. At work I use it more or less all the time. The possibility to change to whatever music you like at the moment is GREAT!
The UI need some improvements, but it's quick and the most important things is that the music streaming really works. I can't remember ANY downtime, and not that many records/artists I have searched for have not been found. Please Spotify, add Rammstein records will ya ;) not only their songs in compilations.
Like it, like it alot!
And finally, Spotify!! Please make me a iPhone beta tester ;)