Well - as always with this community, some helpful responses.
Just pressed the button on an AFX3 and F12.
Paul,
Got to say, your timing could not be better. I bought the Axe FX III relatively soon after it was first available in Europe. Already had an AFX II XL, and because the FC12 wasn't available yet, carried on gigging with that, and the old MFC-101. At the time, they sounded pretty similar, and although I loved the functionality of the AFX III front panel, I was pretty happy to continue to gig with the AFX II. Then last year I finally got an FC12, and the only thing I don't like about it is the lack of gigs to play. I use it all the time at home, and cannot wait to get out and use it live. I have had to move myself out of MFC-101 "reveal" headspace, I used to use that all the time to turn a preset and scene controller into an effects controller. FC12 and scribble strips, and incredible (near on infinite!) flexibility of layouts involved thought, but has meant I don't miss the MFC-101 at all anymore. Couple that with the additional block and channel availability in every preset, and you'd think there was every reason in the world to switch to the AFX III and FC12, but I haven't even got to the best bit yet...
I'm guessing you know how good sounding Quantum, and then Ares v2.0 had become? Since then the firmware has really forged ahead. The drives became unrecognisably better last year, but the latest release of Cygnus has done something completely remarkable in terms of making the amps sound and genuinely feel like tube amps. For me this is most obvious either side of the "edge of breakup", which is where I spend a lot of my life, particularly with Marshall and Fender amp models. I no longer spend ages looking for an IR that might work for a particular amp model, because they all sound good, and by the way the stock IR library now contains a bunch of "peaches" that weren't there before as well. Oh and you can align them in the time domain if you want to too. Like having Cab Lab built into the Axe.
So you maybe will have landed with steeper learning curve than I did, but you will find that it's really, really worth it. There is so much more available, it is so much more accessible, it is so much more flexible, but above all, just sounds and feels so good. If you don't find yourself with a "sh1t eating" grin on your face in the first 30 minutes of playing around I will be very surprised.
Good choices!
Liam