The koxx is a little more flat than the KH. I like my KH even without the gel, but saddles are like shoes in the sense that what fits me won’t necessarily be good for you.
Gel saddles are a little heavier than air saddles, if that’s the kind of comparison you’re after. Gel is supposedly more comfortable than foam. Other than that I can’t help you.
None that I can see apart from branding. The Koxx one has a big logo on it, the others have wee subtle logos.
I don’t see why not.
It’s gel! Same as when you put a gel saddle on a bike. It’s more comfy!
Other than that, the gel saddles are not as tall as a KH. I got one on my coker and it’s well comfy. Never tried it on trials uni or muni but am going to soon, just to see.