What I'm curious about is how knock off's compare to most stock, from the factory, wheels.

I get that knock offs are no where near the quality as the real deal,
but, I myself have broken plenty of factory wheels hitting curbs and crap like that. Hell, even had one of the chrome 350z wheels crack on me pushing it through a high speed turn. I haven't ever had crazy offset or camber or anything like that. Usually stock alignment. Or close to. I took that turn right at the edge. felt a weird twitch. Got out of the turn, slowed down, felt the wobble. Stopped, looked at the wheel and one of the spokes was cracked. Not all the way through, but still.
I get that there is always the far extreme cases and you should really throw those out, but there are enough people out there that have hit curbs, even at parking lot speeds and destroyed their wheels.

flip side to that is I had some enkei wheels that survived my wreck and they were slammed into a 4 inch stone curb, a fire hydrant, and two complete roll overs and they only need some resurfacing.