I would think, and maybe it's just me, that if you were seriously trying to hunt down paranormal activity, you would want the best, most accurate, and most finely made EMF detector you could get, not some bargain-basement handheld. And I would expect you to be concerned with being trained in its use proficiently enough to filter out all the EMF noise that we generate everyday. (Question: Have the Ghost Hunters guys ever tried to do a hunt in a casino? It'd probably be hilarious, given the sheer number of electronic slot machines out there.) I suppose it's like the difference between a trained archaeologist and someone who digs random holes in the ground looking for arrowheads and "buried treasure."