I've had several Martelli cutters for years and years. I love them because I can sit down and cut fabric. I have bad knees and standing and cutting really hurts then and sometimes my back. When I sit and cut, I can cut for hours and I have no pain in my knees, back or my wrist.
I purchased a 60mm and I love that one even more. For some reason the 60mm seems to keep sharp longer. I don't know why, I suppose it could be my imagination, but it does stay sharper longer.
By the way, all rotary cutters should be cleaned and oiled regularly. Some fabrics shed more than others, and they should be cleaned and oiled even more often. The fuzz slows down your cutting. Cleaning and oiling also keeps your blade sharper longer.
If you are afraid that you won't remember how it goes back together, I take a picture of each step as I undo the blade. That way you can see how it looks as you go. I also take of each piece and put it in the order that it comes off. That way you can pick up each piece as it goes back on. Did that make sense.