After testing out Turntable.fm for the past few weeks, I have to almost disagree. And this is coming from someone who worked on Grooveshark Radio for a year, which is almost all algorithmic.
You'll discover music on Turntable, but for the same amount of time spent on an algorithmic radio station you'll probably discover more.
When I'm in a well-DJ'ed Turntable room, the "radio" feels so much more natural. Songs flow. People are constantly editing their queues to best the song before it and I find myself rarely having to vote on a song. Its already better than Pandora, IMO. It also beats BMAT which has amazing algorithmic recommendations (based on waveform analysis and musical feature decomposition).
The only issue I see right now is that if your tastes are outside of Electronica and Indie, theres not much else for you at the moment.