Good, a lot of the time, Pandora plays songs that make no sense. Hopefully a human can keep this from happening with iTunes Radio.
If a song "doesn't make sense," that's what the thumbs-down feature is for.
Personally, I'm saddened to hear that this is how it's going to work. The "radio" in "iTunes Radio" was correct, I guess. If a list is assembled by humans then it's really not much different from how traditional radio works.
I love Pandora as both a music listening service and as a music
discovery service. I listen to a lot of music that isn't mainstream and before Pandora I had next to no way of discovering many of these artists. Being able to influence the "station" by indicating which songs I really liked and which songs I disliked was huge.
I've purchased many songs and albums through Pandora (and would have purchased more, but not all were in the iTunes Music Store). It seemed like such an obvious thing to have a service like that built right into iTunes. I'm not going to disparage iTunes Radio without trying it, but when it comes to obscure songs, artists, and genres, I trust algorithms more than humans. iTunes Radio might not be the threat to Pandora that I thought it would.
Pandora is the extreme opposite. If you thumps up/down enough times, it will literally only play the same 20-30 songs and start looping. It never adds new variety into the mix.
"20-30 songs" might be a bit of an exaggeration, but it's true that you begin to loop songs over the course of a few hours. In some ways it's nice to have that, as it's almost like a "perfected playlist." New songs are added in over time, as Pandora expands their music library.
Variety-wise, Pandora resolved this issue with the "add variety" feature of choosing songs from multiple "stations" as you listen. Have you ever tried it? It works pretty nicely.