OK but does the zapper really work?

Ok this might offend some people, but I've been reading a lot of negative feedback on the zapper. Basically things trying to discredit Dr. Clark and say that the zapper is totally ineffective. I've been looking around on the internet (and this site), for positive feedback, and I'm having a hard time finding any.

I want to get a zapper but before I drop 80+ bucks on one, is there anyone who has used a zapper and has gotten definite results? I would *really* appreciate as much positive feedback as possible, as well as success stories.

Thanks!