Speak for yourself I and many of my friends and family use iTunes Radio.
I use it. I was happy with it, in the beginning. Now my problems with it are:
1. I have to turn iTunes Match on my iPhone and not get bombarded with Ads (which is the number one reason I'd use this over Pandora since I already have a Match account). This used to not be a big issue until with iOS7 turning it on wipes out your sync'd music. Big problem, I frequently end up in areas with no cell service, let alone data service and I don't want to burn my data plan on things I should have access to all the time anyway. iTunes Match overall has been buggy as hell in iOS7 for me, in fact I'm pretty sure it just decides to delete music from my device to make room for other stuff, WHICH I DON'T WANT IT TO. If I download something to my device, I want it there, ALWAYS. Then there was a point where it just decided to duplicate every album I had downloaded showing multiple copies of songs and generally forcing me to start over from scratch. When downloading large playlists, there's no way to easily clear the queue. I think I could go on and on, but generally, I want access to iTunes Radio without being forced into the remainder if the remainder isn't going to work like I need it to. On all of my other devices (like my extra libraries on other computers, appletvs and iPad), it's fine and works like I need it to. Ultimately, why can't I just tell my phone that I have an account and have it work ad free without forcing me to do something else I don't want to do.
2. Then I realized it wasn't working like I had hoped for playing music. I have a pearl jam station and no matter how many times I "don't play this" for songs not by Pearl Jam, iTunes radio insists I want to listen to other bands and I get maybe one Pearl Jam song an hour. Not cool, Pandora in ad supported mode gets this and my Pearl Jam station only interjects another band every few songs and they're generally on the mark. I have another station tagged with a dozen artists all in the same genre, and it's the same thing, I get maybe one song from an artist on the list and then a dozen songs from people I don't want to listen to.
3. Then I realized there wasn't any variety. I started hearing the EXACT same songs over and over again on stations.
I've tried moving those sliders, I've tried adding more "seed" bands and songs. It doesn't seem to do anything.
I'd love for someone to tell me I'm doing something wrong, but ultimately I'm looking to just head back over to Pandora on my iPhone.