I'm looking for a folder as a backup to my main fixed-blade in my BOB, and as with everything else i like to get the most durable thing available.
With the intended purpose of acting in place of the main fixed-blade knife in the event the fixed-blade were lost/rendered useless, what folder would you recommend?
we'll leave price out of the list of considerations for the sake of discussion, but it should be a mass-produced knife, no customs.

to put it another way:
of those who EDC a knife(in general; not just on this site), the majority seem to carry a folder rather than a FB. so that's what we'd have if we were thrown into the thicket with just what's in our pockets.
what folding knife would you trust to hold up to demands if TSHTF?
what type of blade, lock, etc. would be best for this kind of (ab)use?
that's the kind of information i'm looking for, preferably from 1st hand experience, be it from controlled testing or real-world SHTF situation.
not necessary specific brand-models, but a general outline with p maybe a few prime examples.