The older Martelli cutters do use Olfa, Fiskars blades. I don't know about the newer ones. I have a couple from about 5 - 6 years ago.
The Truecut is pretty good also. That guide system can be removed and used like a regular cutter. I removed it from one of mine as Truecut doesn't have some of the rulers I want. I've removed it on both 45 and 18mm cutters.