The other downside to the Kemper vs. the Fractal I found was you are solely dependant on other people's amp captures. Which includes their preamp, mics, mic placement, mic choice, speaker cab, speakers and amp settings. Yes you can tweak some, and there are plenty of good tones out there but nothing is really true to post tweaking of the real amp. Fractal is way more precise and legit to the actual amp settings. It's really all personal preference though. Both exceptional products but I favor the Fractal.
That's one of the hangups I'm having with the Kemper. For arguments sake, let's say the tones from the Kemper are, to some degree, more authentic. I still have a bit of an issue with the seeming lack of versatility and modularity. I don't see a way to mix and match amps and cabs or tinker with the innards of an amp / cab. For me that's a major drawback, but that's me. And whatever profile you're using is a singular snapshot of whatever settings that the setup was using at the time. I don't see a way to interact with the profile to faithfully mimic the effect achieved by turning knobs on the actual amp or cab the profile is based on. In other words, it seems rather limiting given the asking price.