The Sprint Arrive (see review) barely has any Sprint software on it. One of the apps though (not pre-loaded, either) is Sprint Radio.
Two versions exist within the app: free, with 60 stations and some commercials and "extra" which costs $5.95 a month. The latter is for all intents and purposes, Pandora Radio (but it's actually mSpot). It allows you to create radio stations based on your bands/likes, skip tracks, dislike songs, etc. It also has news, sports radio, weather and some other premium content.
For once, we can actually say we're mpressed with the service and if you don't have a Zune Pass, it is worth considering.