I have found Pandora's selection frustratingly repetitive and looked toward using other services because of it. I have made a bunch of radio stations and cycle through them but they always have the same songs mixed in. Now that I have Spotify premium, I see no reason to use Pandora again. Spotify has radio if I want to use it or I can just turn on any song or album I want. That's a big plus in my opinion.
I used to measure Pandora channels in TTC or time to Coldplay. Every station would get there over time.
I don't get there on most of my stations. Maybe you just like Coldplay?