It's kinda ridiculous to keep trying to put distance between yesterday's box and the shiny new one today.
If the Axe Ultra smoked the Standard, and then the II smoked the Ultra,
II Mark II > II
XL > Mark II
III > XL
.....
The Fractal Axe Standard must have sounded pretty bad in hindsight, right?
We all know that's not true so ya, the improvements in sound/feel with each new iteration must be minimal.
I just bought a III. For the last ten years I have been using an Ultra. After a bit of tweaking, I can say that the III does in fact smoke the Ultra. Not that the Ultra sounds bad, but what I'm getting out off the III is much better.
It may just be that the III is so easy to dial that I'm getting much better tones out of the III in a month than I could figure out how to get with the Ultra in ten years, but either way, the III rips.