I recently contacted Spotfiy to voice my disappointment that the Radio function doesn't work on Sonos or Roku. There response was to post on their community and based on the number of Kudos, they would determine if it was important. This is quite unfortunate because if you look at the Sonos message board, you can see this has been a frequent request for years now and is up to 34 pages of messages.
With so many other options, I see no reason to continue my premium subscription until radio is available. I will gladly use another service like Pandora that provides the functionality I would expect in a premium subscription.