Spotify has finally made its way over to American shores (can we have Netflix now) and it is time for you to celebrate because it really is a good service. To run the Android app you do need a premium account but I think it is well worth it.
The obvious feature. Spotify has the option to cache your favourite playlists to your phone so that you can listen to your music without having to count you data usage and data signal strength. You can save the music as High or Low quality and from my experience I find the high quality music to be very good and definitely on par with my MP3's.
Good Social Features
The social features are not on par with Rdio but they are improving with every update. You can subscribe to your friends playlists on the desktop player and they will appear on the mobile app. The playlist will update whenever your friends changes it, or alternatively you can create shared playlists and edit them together. You can even send songs on Spotify to your other friends to listen to, any sent songs will appear in your friends inbox for them to listen to or alternatively Tweet the song and it will appear on your stream for any fellow Spotify users to click on and listen to the song. A good companion app to Spotify is Share My Playlists the best way to instantly find a group of songs you would be interested in. A lot of the social integration is done with Facebook Login so it is fairly easy to set it up and find your friends, you can also search for people by their Spotify username, and you can choose what people see so you can hide those embarrassing songs you listen to.
All playlists are synced between desktop and phone making it easy to access those Playlists you are steadily building up. Recently Spotify updated the desktop app so that you could sort out all your phone related business without even touching the phone choosing which playlists to cache to your phone and which playlists are relevant. You can also Sync your own songs that you own and aren't on Spotify's playlist but you cannot cache these and they can only be listened to while there is an active data/wifi connection on.
All The Music You Could Need
Over 15 million tracks means there is bound to something there for you. Plus with a premium account that music becomes available on your phone and you can listen to the music as much as you want. All that music is still there when you change Android device or lose your device, the playlists never go away. Between the Spotify, Kindle and Market apps changing phones has been made effortless.
The best way to get recommended new music is to use some of the 3rd party stuff found here, but if you no exactly what you are looking for the search button will more than do the job, personally I have found it very accurate, whether searching by song title or artists name it always returns relevant results and gives stats on the artist, song length and popularity if you are interested. There is a tops list as well but you can't browse by genre (hopefully further down the line though).
Anyone tried Spotify yet? If not here are some Invites, as I have already said though you do need a premium account to access the app.