I've never used any Kemper other than plugging in to track a lead after someone picked a tone, curious about the general usability on the fly,
The Helix has an incredible workflow. You only need HX Edit to move blocks between paths 1 and 2, other than that I found it really intuitive and REALLY fast to build/change/save/use, and favourites (block library) don't require a computer. The fact that any parameters in any block can be controlled by scenes or footswitches is amazing, and scene changes were completely gapless for me.
After spending a few weeks forcing myself to do things on the FM9 hardware instead of FM9-Edit, I'm a lot more familiar with where most functions are, but you can't copy/paste a channel which would be useful. The desktop editor is definitely faster for complex editing but if you know what you're looking for you can do many things on the hardware. The layouts being infinitely customizable is far more useful (and fun) than I realized at first!
Bottom line IMO - I loved my Helix for over 2 full years and it has the edge on standalone usability, but Fractal is superior in tone, feel, and overall personalization. Especially once you learn your way around the unit and use a desktop for complex editing, the FM9 wins