So it's obviously more Pandora-like than MOG, but been using iTunes Radio a bunch since its launched and it's a lot of fun. Some have done bitrate analysis. Considering the $25 Match to remove commercials (and backup). This post probably doesn't mean much, but I can say creating the following stations produces some nice music.
Ike Quebec & Lester Young
Art Tatum, Dave Brubeck & Bill Evans
Johnny Hartman & Nat King Cole
Giving Songza a try next.