There is definitely something lost by relying on the algorithms, although I have found some fun stuff using Pandora. I wonder though how much of the decline in less "railroaded" discovery is due to algorithms per se versus the second-order effects that have accompanied the rise of algorithmic listening. An obvious one is the decline of record stores. Another is the decline in radio listening. It's not just that we use the algorithm to listen, but that we use an algorithm instead of other ways of listening, which then causes those other ways to wither.