Pretty much my take too. If they come in sets they're not likely to be very good. Just seems to be the nature of
the beast. Buy them individually as you need them. If you look around you'll see that virtually none of the "good"
brands sell them in sets.
Nachi is my preferred brand but there are many others. Butterfield, Clarkson Osborn, YG, Dormer, Morse, OSG,
Hanson Whitney to name some. Regal is an American made brand that I've never used but I've heard good
things about.
If you want to learn more about taps you'll find a few pages of good information in the Travers Tool catalogue...