I'm not too hasty / judgmental about this - I've built one of each of the Kibler kits, another kit that was on the opposite end of the quality spectrum from those, and one gun from a blank (with help in a class). Maybe I'm just not as handy as everyone else, but even with my most recent Kibler, which was the new WR and the easiest to build, there were a few things that I felt like could go wrong without care. Fitting the brass cap on the back of the patchbox lid wasn't easy for me, but even the routine task of putting the pins in without something going sideways takes attention and care and a little finese. If you've never done it, it can be intimidating.
I frequent another forum for handtool woodworking, and I posted a few pictures of my WR there while I was working on it. I made it clear that it was a kit etc., and an easy one at that, but comments from guys who can build an entire armoire from rough stock with hand cut moldings, without using electricity, reacted like I was the second coming of Jacob Dickert. It's all relative.