I have mainly used the strings from the bowyer on my bows and to be honest don't even know what most are made of. They are what the bowyer used and seem just fine to me.
My guess is you are like 80-90+% of archers. From what I've seen, a lot of bowyers are in the same boat--they may know bows inside and out, but strings? Not so much. They often fall for the same type of hype that others fall for.
I don't claim to be anything special, I just love making strings and I've been making them, along with studying materials, for two decades. I quit counting how many I've made at 10,000 years ago. And I find myself learning more all the time.
Like I said, trying to portray string making as something magic and mystical drives me nuts. It's a fairly simple process that just requires knowledge and practice. No pixie dust, no equipment stolen from the Department of Defense.
That's one of the reasons I've been involved with two string making videos (Doin' the Twist and How to Build a Great Bowstring). When I was getting started (pre-internet)it was hard to get good information. When the internet came along, holy smokes! Lots of information, some of it off the wall! So we did the videos to try and help folks out and clear the smoke and put away the mirrors.
My favorite material, to date, is BCY-X. The reason being is it's 83% SK90 Dyneema (the highest quality HMPE/UHMWPE available from DSM--not a Chinese knock-off) mixed with 17% Vectran (for stability, especially in higher temps).
To me, this is the best combo currently available for the type shooting and hunting I do, in the situations I shoot in. Very consistent, very durable, quiet, great performance.
Obviously I like my own strings. I'm fortunate to know some excellent shooters who have helped me figure some things out. I've picked the brains of beginners and experts alike over the years, along with the great folks at BCY. Rod Jenkins has been a great help over the years--along with being a professional archer and coach, Rod was also a professional string maker.
Knowing what is in a specific material and knowing it's characteristics helps me make a better string, and BCY has always been great about telling me anything I want to know about their materials, what is in them and why.
Not to promote my videos, but if you watch one it's basically the same as sitting down with me at my shop and watching me (which I invite people to do if they are in the area). No secrets, no bull. That's what got me hooked on BCY early on, and why I've used them exclusively for almost all of my string making career...no secrets, no bull.
Anyhow...sorry if I come across a little strong here. I am a bit passionate about making strings.