I don't mean to be rude or anything, but I think your opinion is a little bit biased... There is no evidence for what you said about "Cheap" Zappers, and the vets on here use all different kinds of variously priced Zappers, all getting the same kind of results. I have not heard of any Zappers that don't work, but I think it's wrong to say that just because they charge you an arm and a leg, that it's a better machine. It seems like you should get what you pay for, but I guess you can pay what ever you want for what you get. Anyway, sorry if I seem like a snit, because I don't mean to.
I have heard good things about drclark.com peoples Zapper, but they are often confused for actually being Dr. Clark's own Zapper, when in fact they are not and they are just another company providing Zappers. Feel free to recommend things though!