Ive got the HF 40 piece in sae and metric - the cheapest of the cheap sets. I've also just recently got a big Irwin carbon set as well as a number of individual sized USA (GTD) branded HSS singles here and there.
As for the cheapest of the cheap HF set - they come with all sorts of burrs on the taps and dies than need to be cleaned up. The tap handles and die stock are truly terrible and should be thrown away or used as hammers. The tap handles round out, and also round the shanks of the taps. The die stocks slip and can't hold the die tight. Because it is a pretty complete set, it has saved my *** one time when I needed an M5 to reform some threads on an outdoor lamp post. Who uses an M5 in stuff? Sheesh. Once I needed to extend the threads on a few 5/16-18 bolts (while doing a repair on an elliptical exercise machine)and I decided to use the set. The first bolt was great! The second bolt's threads were really rough edged. The third bolt even worse. Turns out the die itself had a few threads that sheared off. I don't ever try to bring this set out to do anything "important". Most of the time, i might use it for cleaning up threads of used fasteners that I've salvaged from some defunct thing that then goes into my parts bins.
In retrospect, I would fully recommend *against* buying the cheapest set. Consider it to be capable of cutting nicely once, poorly a few times, and then disposed. I was thinking of seeing if I could unload it for $5 on CL, but that seems like too much effort.