I have one of these that I picked up cheap. They're very sharp but a $20 blade isn't going to be made of the best metal. Mine's lasted for years of light use as a box cutter. Anything heavier and it'll likely wear out very quickly.

It's no Rambo knife for sure but generally paying a lot more for better metal gets you easier sharpening or longer edge retention, not overall tool longevity so long as the basics of the design are right - good hinge pin, precision machined locking mechanism.

It wasn't really meant for big jobs though, the handle is designed to be sleek for pocket carry or less space taken up in a small pack rather than give maximum grippiness... well that and the fact that the blade is only 3", too short for tough jobs so it looks like it is meant as a pocket carry with 3" being the legal limit in many states IIRC. It is similar to a Buck knife I have and that design is good for pocket carry, though moreso in jeans or field pants, wearing slacks or dressier it seems a bit bulky.

Kershaw will resharpen their knifes for free. You pay shipping to them, they totally redo the blade and you basically get a new knife back in the mail (they pay return shipping).
Nice to see service from a knife vendor. These guys rock.