I also used to be a kemper user also back in the day. No shade on the kemper or its users, but for me and my needs, Fractal just out performs in everything in my opinion. I did enjoy it though, but I hated having to buy profile packs and then going through 200+ profiles to find the right one. And the big one was recording for me. And more power to those who can get a really good quality guitar track sound from the kemper, but I just could not to save my life. Something about the low end just never sounded right. And I tried EQing it til I was blue in the face....but just couldnt get it sounding right. Probably user error on my end I suppose. But guitar tracks always sound killer when coming from a fractal product.
There's always been a marked difference in the low end between my amps and kemper profiles of these amps, plus a ts focus that's always there with gain sounds. How recognizable it is largely depends on the kind of test. At times, it's easier to feel this than hear it -- but it's still there, struggling to come out, like pterodactyl.
I don't believe fractal units are perfect either.
People will say there's "no fractal sound" (unclear what this characterization often means, ok) even if a newer firmware relatively consistently changes tones between a variety of amp sims, and so forth and so forth, claim an amp sim is "spot on", which then changes as well, relatively considerably.
A big difference for me is just that fractal evolves the core amp sounds. Kemper does not (not for a long time at least). Where as you can expect Cliff to continue seeking improvements, CK will drum the same beat.
I've compared cygnus on axe fx 3 with ares on the same unit and on fm3 -- the JCM. I can see why it's closer now, even not having Cliff's specific amp (or I believe it's likely I do see the difference, and why it's closer to his amp even, having spent an hour too many with such comparisons).
With kemper, when i profile the jcm, I know what I'll get, and I know nothing's gonna change any time soon, other than more marketing style posts perhaps.
It's not that kemper is bad. I can even see people preferring kemper sound to fractal, whether with ares or even Cygnus. Such evaluations are based on such metaphysical subjectivity. There's something about kemper's response you just don't get with fractal right out the gate, cygnus or ares. (Well. Engage considerable mid compression, plus a few other tweaks and you'll get close, but never 100 percent, at least not through every single reasonable -- for me specifically -- means of evaluation).
Personally, I prefer fractal. But I also trust them more to push forward considerably further for core amp tones. That also matters to me... And I wouldn't say I'm a "fan" of either company, at least in some exagerated, loyalist sense. I don't wake up, put my fractal or kemper panties on, before coffee, proceeding to sacrifice sheep, cats, donkeys on the altar of cliff or lord Ck or god knows whom.
But at the end of the day, when Cygnus feels better to me than kemper, I'll go with that; and I'll be glad to receive updates that inspire me as a player, as well. And I also do respect the fact that cliff still pursues core improvements to this day.