They sure do put on a show but are quite harmless as the pincers aren't functional. Nothing like hearing a loud buzzing in the dark and having one of those things run into you (that happened to my wife).
It was funny, he was walking right out next to the castle and a group of tourists gathered around when they saw my son holding him...a few of the people could not be convinced that he was real, even after he walked around on his own.
I'd imagine that they're edible, but I'll wait to see what someone else thinks of the taste before I try them :) They live for something like seven years underground as a big, fat grub (probably better eating then) and then emerge as a big beetle and mate and then die. I've read that some entomologists think that they never actually eat once they reach the beetle stage...the pincer/antlers are for duals with other males and aren't capable of delivering a pinch.