I carried this knife when I was a kid, 12 years old on through young adult. It used to be sold in Field and Stream as a "German Survival Kit" knife. I guess because of the thin profile. I carried it a lot because I thought it was cool to carry in my sock like a punk bad*ss. I ended up getting it whenever I needed a knife because it just cut better. No clue on steels and such at that stage of life.
Fast forward to 10 years or so ago (I'm in my 50's) and I pick up two Mercators for a trip down memory lane. I get them and the blades are a bit warped and other stuff... "boy they don't make them like they used to".
I took one to work and spent about two years trying to hurt it. I cut whatever, scraped, and did a lot of cutting plastic by hitting it with a heavy plastic deadfall hammer. I nicked and gouged the blade and sharpened it out and went on. I actually quite like the steel. I finally bent the backspring, took the knife apart, bent it back, and I still have it.
It's a lot worse for wear and the lock doesn't work at all now but it's still serviceable and the darn thing surprised me at how much it would take. The lock didn't hold up to real abuse and got worse with wear but you should never totally trust a lock anyway. I can't say if it's better or worse than any other lock. If you back pocket carry the knife it will prolly bend, I had that happen as a teenager. It'll also keep right on working I'm sure.
The one thing I do NOT like about a Mercator is that the tip hits a piece of plastic inside the handle to stop closure instead of the kick hitting the backspring. Thus the tip gets dulled. This is a pet peeve of mine and one I wish people spoke of more when they reviewed knives. Many otherwise great knives do this (EKA?).
Other than that, a Mercator is a great, workhorse of a knife.