I don't know much in the way of electrical engineering, but I think the complexity possible is fairly close, but its likely easier to judge a hardware design as

I don't know much in the way of electrical engineering, but I think the complexity possible is fairly close, but its likely easier to judge a hardware design as being sound since it ultimately has to tie back to reality. I think the complexity of software is that it's almost completely abstraction. So the question reminds me of someone asking, "What's harder, physics or philosophy?"