I got to compare both the Zutter version and the Chomper at a recent Scrapbook convention. Both punch beautifully, but, and this was HUGE for me, the Zutter cannot punch just a single sheet of CS! It's designed for stiffer and thicker materials and the manufacturer warns you that it doesn't punch single sheets. The Chomper does punch both types -- thick and thin. It's fantastic! I use it all the time!
I also bought the Fiskars flip punch awhile back, did not like the quality of this thing. You have to carefully position the corners into the tool if you want a clean corner. Save your money and go with the Chomper!!