Thanks very much for the info, Karenkcoulter.
This is the first post I've found with a quantifiable rate for iTunes Radio. However, if 18.3 MB in 26 minutes is accurate, the bit rate is extremely disappointing - to me at least. Your bit rate (over an LTE connection even) was only 96 Kbps. Here's the calculation: 18.3 * 8 * 1024 / 26 / 60 = 96.1. This is still better than say, Pandora's rate of 64 Kbps (AAC) but since iTunes already has an entire library of 256 Kbps AAC files that they use to stream iTunes Match songs, I was hoping/anticipating they'd be doing the same thing with iTunes Radio. Or at least make that option available. I suppose that 256 Kbps is perhaps a bit much for some cellular connections and/or data plans.
I really wanted to ditch MOG's $10 per month plan when iTunes Radio came out but the sound quality of 96 Kbps can't compare to MOG's 320 Kpbs, even though I'm assuming that Apple is streaming the superior AAC codec as opposed to MOG's MP3 at 320 Kbps. (If anyone is curious about the codecs, just do a quick search for AAC vs MP3.)
I know I'm basing all of this on a single "test" and iTunes Radio hasn't been officially released to the general public yet. I'd really be interested in seeing anyone else's numbers.