Yes there are quite a few Spotify clients available at the moment.. But I think that also can be a good thing to some extent, however I think the suggestion of a Maemo-Spotify team sounds like a really good idea! The best features from all clients could be combined, and more focus could be spent on stability issues etc.

At the moment all N900 Spotify clients require a premium subscription, and I think this is a restriction that we will have to live with. Spotify has also restricted use of their official mobile clients to premium subscribers only, and e.g., the despotify team has decided not to circumvent this restriction. Also the offline functionality is something that probably will not show up in the unofficial clients in the near future (even if its implementation should be quite straightforward), as this would easily enable to download music directly from Spotify.