Great post.
I agree with the general take I get from this - they've got some surprisingly good stuff, some stuff which is cheap for cheap money, and some garbage. I'm still ahead on what I've bought there to my mind, and I've spent a fortune.
I do real construction. Mostly not with HF stuff, but some of there stuff stands up to it. And other times, its nice to have 6 HF tapes lying around at $2 a pop when I can't find my $30 tape.
You get a feel for what you can buy from them and what you can't to my mind. I won't buy much in the way of precision tools there. I have the calipers, which are pretty useful, but I don't use them precisely. No way I'd buy a harbor freight level. Don't know for sure they are off, but I wouldn't take a chance.
On the other hand, how can you mess up a sledge? They don't, and I have pretty much every variation they sell.
Pneumatic Pex air hose is just as good as any other I've bought. Anvil seems fine.
Roofed and sided my new barn with the Mag roofing nailer. Works great. I've had really good luck with all there air nailers. That said, I don't buy my primary nailers that I use all the time from there - just stuff I use occasionally. I'm one of those that thinks there are 2 kinds of framing nailers - hitachi and junk.
Harbor freight clamps are pretty awful. I've even broken a pipe clamp from there. That said, on most of my HF clamps I've got more than my money's worth.
Drill Bits are pretty bad.
Hand tools seem pretty good. No obvious issues so far.
Frankly, I've had a lot of good luck with tools from there. I even have a stack of catalogs next to me to go through (I find their prices can vary dramatically catalog to catalog). I'd say 1/3 of their stuff is junk, thus a combination of a feel for the place and prices that are more than a third off ends up with me way ahead