Pandora has always been awful. I remember putting on MC5 & The Stooges and getting Foghat

, Echo & the Bunnymen plus Devotchka equals Starship 'We Built this City!'

Tried Last.fm years ago & although they made no "One of these things is not like the others, one of these things just doesn't belong" mistakes, the track selection was pretty limited.
Anyways, even though I'm currently subscribed to Tidal, Spotify's recommendations were good enough that I constantly considering going back (very well might if I get a more forgiving dac/amp/speakers one day). I discovered many great ambient/electronic/industrial-soundscape/quiet-drone artists through them. The issue is that after a month of listening to new sounds, they forgot I also liked indie pop/rock/etc. Can't comment too much on jazz or classical, but its at least competent: listen to Charlie Parker, get Dizzy; listen to Ravel, get Debussy.
Lately I've been using 8tracks.com which is all user-submitted playlists. Admittedly they're rather hit or miss, but you can usually tell a bad one by three tracks in, and the good ones can be very good indeed.
I've read many good things about Roon, but the price seems very steep considering everything that's available for free.
Kirk