I am unabashedly a HF fan, I buy a good bit of 'stuff' there...
I think I have 2 items that jump out as a super bargain and astounding wearability -
First would be the 4 1/2" angle grinder (orange one) that sells for around $15 - I have had mine for some 10 years and it just wont seem to wear out, its a bit noisy now, but still chugs right along, whether grinding, cutting, sanding, etc.
Second would be the air die grinders in the straight and angle versions that sell for around $15-20, I have 5 of the straight and 3 of the angle with different mountings - with a cut off disc being one of the more handy tools in my shop, with a 3" sanding disc being awfully handy, also grind stones carbide cutters, etc. Here again, I have a couple that are some 6-8 years old and they just keep a going.
Nothing comes to mind right off as to 'bad' stuff. Tho there is some crappy stuff there, it seems to be less common than in the past (as does the import tools across the board)