I have a Kaff and have a very love/hate relationship with it. It was bought as a winter road bike, fitted with guards and 28mm tyres and it worked perfectly in that function. But. But it is/was so dull to ride, no spring, no life in it, just plain uninspiring. I suspect this is down to the weight of the frame (not light) and more likely the wheels (mine are the standard On-One Reetard wheels), I should likely buy new wheels but I’m reluctant to spend money on I bike I don’t really like riding. It’s now got to the point where I prefer to ride my old summer bike (23mm tyres, no guards) all winter.
However, I recently took the guards off the Kaff, put on some 33mm CX tyres and starting riding it along tow paths and gravel roads and suddenly it makes sense, I like riding it again and I feel like I’ve found what it’s meant for.
So, to conclude, if you’re buying it as a all weather road bike, don’t, it’s dull, boring and not fun to ride. But if you’re buying it as a gnarmac/gravel bike then do so, this is where I’ve found mine come to life.