I needed to make a 3/4" hole in a 1/8" thick mild steel angle to repair a cart. Didn't have a drill bit that size and quickly realized that a hole saw would be a better choice. Off to Amazon. After some browsing, found the same 3/4" carbide-tipped holesaw from a million resellers. Found a package of two for $13. Following the logic of "even if they only last for one hole, it's still cheaper than buying a good drill bit that I'll never use again", I ordered it. Item arrived and it looked as cheaply made as the photo!
But what do I have to lose? For $13, it's worth a shot.
Chucked up the holesaw, dripped some cutting oil on the metal and went to work. Fricking thing went through the steel like it wasn't even there. I was fully expecting that the teeth would chip off and go flying about halfway through, or it wouldn't do crap and the metal would work-harden, making my job even harder or worst case, the entire flimsy-looking thing would shatter (I have excellent safety glasses BTW). No, about 1 minute later I had a nice clean 3/4" hole with perfect edges that didn't even need deburring.
That led to the first Amazon review that I ever wrote: I was that shocked at how well it performed. Turned on my (Amazon-bought) stick welder and finished the repair.