I've noted that when Spotify makes up an artist radio or a Discover list, it doesn't do it by linking artist by how they sound, or to wich style belongs. Insted of that, it seems that Spotify groups them for other reasons. I.e.: if you want to start Led Zeppelin radio, you get artists of that time of rock history but not related to the kind of music and sound of the bands. That is so wrong. Another example, if you wanna hear the Pupa Jim radio, a reggae-dub artist from france, but sings in english and has an electro-minimal style, Spotifiy brings you a weird list of french reggae music that sounds very different! That's not the way, people. Last.Fm and Grooveshark were far superior on this. Pay attention to how the bands sound and the style they play, that's the key.