when i go looking for a tough hard use folder i realize that the job can be done far better, far quicker, and far safer, with a larger fixed blade knife.
for me a "Hard use" folder, is any folding knife that in and of itself does not require maintenance for the period of time i expect to be using it. for example, if i go camping, i want a folder i can use for everything that will have a tough as nails blade steel with excellent corrosion resistance and actual liners in the handle. one with tight tolerances so i dont have to lubricate it every time i get it wet. also something i can use as a go to knife and not have to worry about breaking it. my best examples of this would be the lion steel SR1 in titanium (coated blade), and the hinderer XM-18 3.5 inch (duratech 20cv spanto flipper) i also love stonewashed blades because i never worry about scratching them up.