At the same time, a great deal of effort is spent on ergonomics and other such human factors issues. In many ways, the more modern something is (or newer versions of the same product), it should be easier to use. Take fore example, Microsoft Windows....ok, bad example. But look at various websites, the newer cars, MP3s, automatic transmission vs 'stick'... in many cases there's a bit of a learning curve, but frequently that is clobbered by the power of the newer capabilities.
IMO, it sorta depends on many issues. Technical sophistication, safety features (conceivably, there could be some type of IDing so only 'friendly forces' use the weapons, and man-machine interface. I would think consumer products would be a bit more intuitive than products with a heavy military or technical bent.
My best,