the X-42 Field Knife, with the BG-42 steel, is a great knife !!
the newest version of the Field Knife has S-30V steel. I'm not at all familiar with that steel.
I had the Field Knife w/ BG-42.... it was a pain to sharpen (I'm very sharpening-challenged) but once sharp, WOW !! My pal Tim put some sharp on it, as I recall he said he could carve fingerprints from his fingertip. The blade said RC62 as I recall, and that is some kinda rock hard which also contributed to hard-to-sharpen. But what an edge it would/will take !!
I now have the Recondo w/ BG-42, same thing: the new version has the S-30V steel.
Cheers,
Carl