OK so I got it this week (Tuesday or Wednesday, can't remember) and I've been putting it through it's paces. Thanks to ethomas I had a pretty good idea of the sounds possible, but I figured I'd start with just factory presets until I learn the ins and outs of how to build presets and so forth. The first thing that struck me compared to the Kemper is that it seems easier to dial in great tones right out of the box on the axe. This is one of the things that some had commented about the KPA...they thought it was easier to quickly dial in great tones more so on the KPA than on the Axe. My experience was the opposite. While most of the KPA presets sounded lifeless and "flat" to me out of the box (with a couple of exceptions), many of the Axe presets sounded great. Maybe those folks meant "more accurate to the original amp" or something, but I'm just talking about usable tones, including effects and such. I probably could have added effects to the KPA and gotten to the same place, but the Axe has them right out of the box.
One thing I've noticed is that there is a wide difference between the gain and output settings from preset to preset. It seems to me like these should be normalized across the board and then users can adjust from there. Instead, some presets sit right in the range for my guitar(s), others have the input gain way too high; others have the output settings way too high. That makes it a bit hard to compare apples to apples. Still, many are just fantastic sounding right off the bat.
I will say, the number of options to make adjustments is crazy overwhelming. I've read through the manual a few times, watched tutorial videos, etc, and I still feel like I have barely scratched the surface...because I HAVE only scratched the surface. I feel like I barely understand anything...even basic things like how to set the MFC up to use it for a live performance. Having it change scenes by default is great, but then I can't figure out how to change the preset itself. The up and down buttons seem to jump up by intervals of 5, rather than by an individual patch. Is there a way to set it so that the up and down buttons go up/down by a single preset instead of by 5? That way I could use those buttons to change presets and the 1-4 buttons (I have 5 set as Tap) to change scenes. Anyway, this probably isn't the best place to ask about that, but one of the things I've run into as I've tried to get up to speed.
All in all, I'm really happy with the purchase and I'm having a ton of fun. I don't feel confident enough to use it live yet until I have a better grasp on what I'm doing. I have no reservations in terms of tone, audio quality, etc, though, and that says a ton.