I've found the Steel FAQ to be really good reading.
My understanding of the FAQ is that relative performance among 440A (not used by Buck), 425Mod and 420HC depends a great deal on the heat treat. But, as a group, they aren't as abrasion resistant as 440C.
I have Bucks made from 440C, 425Mod and current 420HC. I can tell a difference between 440C and the other 2 in terms of sharpening and edge retention, but I can't really tell a huge difference between 425Mod and 420HC.
I find the 440C to be significantly harder to put an edge on if dull. I use a Lansky system with non-diamond stone and have to really lean on the course stone to make progress with the 440C if it's badly dull - much more so than with the others. But, when cutting wood and whittling, the 440C holds the edge for longer.
BTW, all things aren't equal in terms of edge profile. My older 110 and 112 both had the "hump" behind the edge that Buck used to use. That made initial sharpening and breaking in the edge harder.
Hope this helps.