Absolutely agree with OP, Spotify has a serious problem in product quality. Few examples:

* Totally inconsistent design - I think they are now rolling out a complete redesign to address this

* The current website was absolutely clueless of states when first released (i.e. showing signup buttons for logged in users)

* HTML views in the app shows/loads incorrect data

...and the list goes on. I started using Spotify when it was still invite-only in Northern Europe and converted into paying customer when the Android app came out (2009 fall I think?) but switched to Rdio recently due to all the problems with the service. The underlying streaming tech is rock solid but everything else seemed to go down hill release after a release.