An early member of the forum—the Spaceman—had one I think and liked it. I rode an ST1300 with one for a week and never really got the hang of it. Like all throttle locks it works well when nothing—gradient, wind speed, your position on the bike, etc—changes after you've set it.
I personally would never have cruise control on my bikes , my wrist do not bother me at all. Even in my cars I use it very little compared with years ago in the North East.
Yes, I have one of the Kaoko for nearly 2 years now, however, I am not too happy with it. The idea is great, however, in practice, it is not user friendly.
The $15 plastic design mounted on the throttle will do the same job and easier to use.
I am not happy with mine and will not recommend it.