I don't have much to say on the edge holding of either. I find both to be appallingly inadequate for my use though I have developed an M4 habit and may not be in my right mind . . . though the place my mind is now in is very desirable and I don't want to return to "The Real World".
That said I will say I had the occasion to do an impromptu fail test on an Opinel #12 and used in a prying motion the blade was almost or practically INDESTRUCTIBLE.
I'm not exaggerating !
Here is what I did :
I cut a slot across the blade with an abrasive cut off wheel on a power grinder. The notch was half way deep in to the blade about two inches from the pivot. I wanted to snap off the rest of the blade at that point to make a heavy duty sort of box cutter knife out of the #12. I put the handle in a padded vise across the pivot and took huge channel lock pliers to grip the blade to break it off.
I couldn't do it ! ! ! ! Here is a link to the final mod LINK > > >
Even with the stress riser in the blade at a very vulnerable point the blade just bowed way, way, way over and came right back to its original position. It didn't even get bent ! ! !
Finally after like six tries of bowing the blade way further than I would have ever thought I would in a million years I finally broke the blade off.
That is one killer good example of a durable knife blade.
The trade off is you have to touch up the edge more often than the high HRC super steel knives which snap right off if one were to try that.
Edge holding on a SAK or Opinel ?
Nah dude, nah.
Both are just too soft to be much of a topic for discussion.
PS: I carry and use SAKs every single day and I am in the midst of another Opinel #12 project / mod.
Not saying they aren't fun knives.
Just keep that Spyderco M4 with you for cutting the challenging materials.
Like traditionals instead ? I just bought a Cold Steel Ranch Boss in S35VN
Now we can discuss edge holding.