What could be better than the ubiquitous Exacto #11?
I found out today. I had to do some hand work on some polyurethane parts I'd made (Duro 80, FYI), and my ol' #11 wouldn't do a thing. This is the stuff that skateboard tires are made of. To machine it, I froze it in liquid nitrogen. That's colder than a witches'

, that is. I had to blend two arched surfaces that were 90 degrees apart, with no fillet radius. Hmmmmmm. Needed a really sharp knife.
Thus, the Martor "Boy No. 72". The blades are an almost exact duplicate (won't say 'copy'), except the slot is either shorter or longer, can't recall and don't care. As we fishermen would say, these blades are "Gamakatsu" (Japanese for "damned sharp", they claim). Handles are ok, too. But the blades are Solingen Steel. If you know blades, you know Solingen Steel is the best stuff going. I Googled for "Martor" and got this url for youse guys.
http://www.martor.com/cutters_artwork.html Checkitout. They got some really neat tools, so look around the whole website. But the artwork tools should be most useful.

Steve