I have a Martelli Ergonomic rotary cutter which I hate, only because the wire which should act as a spring for the blade cover will. not. stay. on. Even. for a. single. cut! As a result, the blade is perpetually fully open, and very dangerous. I would love the cutter if they hadn't put in such a cheap, ineffective wire holder. I understand this was changed with their newer cutters. Would like to tell them where they should stick this one. To boot, it was expensive!
Just want you to be aware of this if you consider a Martelli cutter---make sure not to buy one like mine.