Badhammer,
One of the differences is the hardness, as reported by Buck 55Rc vs 58Rc.
Now... lots and lots of pocket knives have been made with steel in the 55Rc range (or lower). For a great many years, SAKs were in the 54-55Rc range. Opinel's Carbone still is in the 56Rc range. Case 420HC is in the softer 56Rc range too.
I've found that blades in these lower Rcs need to be sharpened at a more obtuse angle to prevent edge rolling and conversely, I can live with a finer angle on blades with and Rc at 58 or there abouts. I keep a Case 316-5 in my kitchen and I have to touch it up constantly. My 420HC Bucks and my Opinel Inox (12C27 at 58Rc) hold an edge noticeably longer.
I gifted an 420J2 Buck canoe to a buddy of mine and he complained almost immediately (and politely) at its inability to hold an edge. Last one I've purchased.