I'm in the 23% on the American side of the chart that uses Pandora. I don't see any reason to switch. I've been working on it knowing my preferences for like 20 years now.
At some point Pithos stopped working, or started working poorly, and I switched to Spotify. The integration with multiple audio sinks that let's you play on any number of networked speakers is a killer feature for me. I loved Pandora but Spotify is a better Pandora (and admittedly more expensive).
In my experience, it's a lot of music that I already know I like. I don't feel like I get much given to me that I wasn't already aware of. With Pandora, you create stations that are based off of a specific band or song. If you are listening to a Rage Against the Machine station, you're going to definitely hear Rage Against the Machine and then stuff that is similar. What I do is put it on shuffle for a group of selected stations and that gives me what I want.