I'm confused about the length and depth of the outcry over Zipper copies. As this picture sure looks like an improved version of the 40+ year old Zinger, I'm not sure what needs defending. Why isn't anyone trashing the obvious Zinger/Zipper allusion? Would you be trashing Erik if the inventor of the Zinger were still alive and posting here?
Except for Steve Roberts, few people seemed too concerned about Tom Monohan coming out with another version of Steve's rug duster (which was also an improved version of a 40+ year old machine) so is the problem that a tool is being copied or is this just the desire to defend someone that seems like a nice guy? (<competitive advantage btw)
I'd counsel Erik not to waste any time responding to posts that make it seem like you're squaring off against other manufacturers. Spend time the same way other successful manufacturers do: branding, continuous innovation, cutting costs, and sharing some profit with salespeople. Focus on what makes your product a better buy and don't worry about anything you can't control.
PS: As pragmatic as all guys say they are, the vast majority will still make purchasing decisions on an emotional level. You have a handle on that, or you wouldn't have bothered with hex bolts and chrome-plated brass. Good luck!