Solved the problem of music randomly not playing. All the music that wouldn't play were files locally stored on my computer, so I "unlinked" them (whatever that means) and removed them from the "local files" playlist, they work fine now. Stuttering seems to have gone away on it's own, at least for now.
I realize this is an older thread. I am having the same issue with Radio not remembering my likes/dislikes. Sometimes it remembers, others it is the same track as before and it still presents me with the option to like/dislike it. Other than that everything seems to work as I imagine the Spotify team intends it to. My installation is like 2 days old on a fresh Windows 8.1 installation. I checked the URL's of one of the repeat tracks and it seems to be the same as listed below: