I've used one. I don't mind the safety/cocking device. I think such a device is actually quite useful on a rifle which may be carried a lot with rounds in the chambers. I find the uncocking device on my bolt action Mauser M03 very useful and more reassuring than a usual safety. Given the barrel must still be pointed in a safe direction but it is more reassuring.

I think for professional hunters a decocker on a double rifle would be an excellent idea. The DR could be kept loaded but decocked and carried far more than it is ever shot.

I don't mind the Germanic styling of the Kriefhoff's but do prefer a more English styled DR.