The guy who wrote this obviously rates it highly:

0-1 is perhaps the most forgiving of any knife quality steel other than the very simple alloy types, and produces a blade of excellent quality for most normal use. It can be heat treated very easily. Further references? Well, the ole' master, Cooper, used it for many years and folks do love his blades because they're tough. Awhile back, one of the best of the blade smiths said that well treated 0-1 would out cut any Damascus, and no one argued with him. Edge holding is exceptional. 0-1 is precision ground unless you're lucky enough to stumble across some mill bar. Goof up the heat treat and 0-1 will let you try again as often as you like, as long as you don't overheat the metal. Tough on grinding belts.