I have it and it's pretty amazing and very simple to use. Even the set-up and clean-up can be done right in front of the spectators without any fear of giving anything away. That being said, the only thing that I find is a very small minus is that the effect is 2 seconds long. You borrow the bill/shirt/sugar packet/playing card etc. put the key through it, and then heal the rip. Compared to pen through bill which is a 3 phase routine.
But apart from that, it's an excellent product, I highly recommend it.