Thank you for this cool service - and for bringing it to mobile platforms too. It has huge potential and I hope you will put the time and ressources in to keep developing this! :)
Now, I really like the Spotify desktop version. It's easy and fast to use and most of the design is kept quite pleasing without sacrificing usability. However, this stands in clear contrast to the Android app, including the beta. I know that the app is not that old but still, a lot needs to be done if you don't want to frustrate people like me enough to just use something else.
The far biggest problem with this app is that the Play Queue needs a great overhaul. In the desktop version this works very well. The Play Queue is right there in the left column, along with all other playlists and sorting options. However, in the Android version you have to open the playback panel, press "menu" and select "Play Queue". In the beta I haven't even found a way to access it. Why not just put it alongside all the other lists in the main menu, like in the desktop version?
Then, when you finally find it, you can't actually edit it in any way. It's extremely frustrating to not be able to edit the play queue since that's the entire point of having a play queue in the first place. That you can shuffle around tracks in the exact order you want them so you don't mess up the actual playlists. It's a vital part of using the program for music at a party for instance, since you often need to reprioritize tracks. Take a look at pretty much any other music player like Winamp or Grooveshark and see how much easier it is to use.
Why is this a big problem? Because actually, mobile devices are very well suited for e.g. parties. What my friends and I do is usually to connect a bluetooth receiver to the stereo and then use mobile devices for selecting music and streaming it wirelessly to the stereo. This is awesome because now you have e.g. a tablet that can play music wirelessly, on battery, for about 8 hours - usually enough for the whole party. It can easily be handed around between people sitting around a table or standing in crowded areas. A laptop can in no way compete with this.
Try doing this experiment at the Spotify offices
1) Have a party for your employees (:D)
2) Load up a tablet (or phone) with both Spotify and Grooveshark and launch Spotify
3) Hand the tablet around and let everybody pick 3 tracks
4) Give the tablet back to whoever is mainly in control of the music
5) Let this person decide the order of the tracks in the new play queue and add new requests where they seem to fit
6) Let different persons be that person
7) After a couple of hours switch to Grooveshark and repeat from point 3
In my experience, Grooveshark will be much, much better suited for this. People need very few instructions and if they accidentally just click on a song instead of queueing it, it will just be put in the play queue after the current track and start playing. With Spotify, usually people spend a couple of minutes trying to figure out how to actually use it, then give up. You can try instructing them but the interaction design is so complicated that you will have to show the same people over and over how to do the same basic tasks. If they accidentally click a track instead of queueing it, the entire play queue that has been build will be overwritten by whichever playlist people have selected the track from. This is extremely frustrating for everyone.
Please, do something about this. We really want to use Spotify since a vast majority of us actually use Spotify when in front of a computer and most have their playlists there. It's frustrating to not be able to use it because of something as simple as this. :)