http://articles.guitarforum.co.za/reviews/review-eleven-rack
I can't compare the modelling to the AxeFX as I've never used one, but the AxeFX definitely has a much more comprehensive effects setup. The amp modelling is good - most amps on a par with the new Line 6 Pod HDs (except maybe on the heavier amp side - the HD's Mesa and Ubershall amps are wonderful), but the HDs have much better and more FX. The Eleven rack also has a good, clean mic input and preamp so is a bit more of an all-rounder in the studio (although I dislike that it only integrates properly with Protools and not with other DAWs).
While the POD HD300 and HD400 are relatively crippled for the serious effect user, the HD500 looks very good - still limited compared to software like Guitar rig though. And how long before Amplitude and Guitar Rig both update their modelling? [/devil's_advocate]. I'm also wondering if/when Line 6 will come out with a "Pro" rack version, the way they have with the other PODs.
Any more specific questions, ask. Must run to a gig now...