Sirius is the only decent music discovery service for me since there's some actual human curation going on (at least on their main channel lineup). Spotify is nice when I have playlists prepared and ready to go but that takes work and I get tired of most of my playlist content after a week. Discover Weekly is garbage, and Google Music's version was far worse. Never tried Apple music.

But I've also noticed the repetition on SXM but I've settled on 3-4 channels I like so I switch between them to combat staleness.