I was looking into maybe swapping my Kemper for a AxeFX II when I heard a demo where the AxeFX sounded clearly a bit better, and I thought it might be nice to have something that was more “amp like” when tweaking.
I quickly got over that. I poured over dozens of demos, and it seemed to be a crap shoot as to whether the AxeFX beat the Kemper or vise versa. The conclusion I came to was, if the Kemper sounded worse, it was most likely due to how the profile was made or tweaked. I don’t think that even the AxeFX III is better than the Kemper. It’s just a different approach.
One other thing I am noticing is, that I think for some types of amps, especially high gain models, it’s probably better to profile it with a DI/load box of some sort, and then use a cabinet from another profile or a converted IR.
They're very different tools which makes them incomparable in many ways. I think you can find many good sounding examples of both doing many different genres. If you can't make them sound good then the problem is most likely somewhere else. Mic positioning on the cab has a huge effect on your sound and limiting yourself to just use one mic, mic position or even just one mix is limiting quite a bit of potential.