First of all- This is a question born out of curiosity. NOT looking for controversy.
I have read many times on here about 'well made strings'.
My question is -What makes a well made string, and how does it differ from a poorly made string?
Making the twists nice and tight,even tension in the separate bundles.Getting the proper back twist to produce a nice round string.
Even strand tension, even bundle tension, correct back twist, not too much or too little twist in the string, correct serving size for the type nock being used, correct loop size, tight and even twists (Flemish), not over or under built...probably several other things I'm not thinking about at the moment.
The difference can be noise, durability, tuning problems, and how it looks.
Dittos what Chad just said. Getting the correct length is a biggie for me.
Enough pre-stretch that you are not adjusting every 10 arrows.
Everything the guys listed above... and I would add that I work on making a tight braid of sufficient length when forming the loops which should be the correct size for that particular bow.
A well made string consists of keeping all the strands separated while tying everything together at the same time. And to keep everything neat, clean and tightly woven.