Joe, I agree it should work very well as long as the teeth on the jaws are sharp, but I don't see what advantage it has over an ordinary Stillson. The demonstration test on the prototype Stillson that convinced a tool manufacturer to licence and produce it, was proving that if you clamp a piece of waterpipe in a pipe vice and apply a Stillson to the other end of the pipe, you can easily twist the steel pipe until it breaks.
Stillsons are rather clumsy in my opinion, so I seldom use one until one of my trusty gas pliers has failed to do the job. Either a Stillson or a gas plier will easily bite into mild steel to the depth of the teeth on its jaws, then tear off that amount of metal right around the object it's gripping. Of course that is rather uncomfortable on your hand in the case of a gas plier.
