What Is 420 HC Stainless ?  Is it any good for a knife blade?  Does it take a good edge?  Will it hold a sharp edge?  I saw it here:

Buck Vanguard

Is this a decent knife or what?

Mike, it all depends on the heat treat.  420 has a nominal chemical analysis of:

C .40 - .54
Cr 12.00 - 14.00
Mn .50
Mo .60 - 1.00
V .20 - .50
Si .40 - .80

which means it is a bit light on carbon and cannot attain the hardness of its big brother, 440C, or some of the better stainless steels available today.  However, with the amount of chromium present it is definitely stainless.  The border is usually considered 13%.  The relatively low carbon content  means that heat treat must be optimal.  Cryogenics would almost be mandatory to ensure a good performing blade.  I have no idea how Buck handles the heat treat for that knife.  420HC is typically used because it is very easy on machine tools and stamp presses.  It takes a very nice polish.  I would say that with a reasonable heat treatment it should perform decently.  I have heard that the hardness runs in the Rc 57 range.  That is a bit on the soft side for a working blade, but it should take a decent edge and be easy to sharpen.