My favorite part of SomaFM is that I discover new artists (or get encouraged to go on a deep dive) fairly regularly. I've never bothered with Pandora or Spotify but the impression I get is that SomaFM is much better with the more niche genres.
I find the same. I feel more "weight" in a choice made by a human, who has their own "map" of the music and what connects it … so, I care to know about the choices made and why they were — the context of the choice.
I'm happier with a song pairing that has some arbitrary, personal history than one that's a logical walk down a relationship model.