Tons of variables in how the string is made, even more opinions...but sorting out string materials isn't really as complicated as it may seem.
Currently there are only 3 basic types of string materials (not counting primitive materials like silk, linen, sinew, hide, plant fibers, etc.).
#1. Polyester. Most everyone knows it as "dacron". B-55 or B-50. Safe for any bow, has the most stretch, the most creep, the least duribility, transfers the most shock. Comes in different grades. B-55 is a slightly higher grade than B-50.
#2. HMPE, UHMWPE. High Modulus Polyethylene or Ultra High Molecular Weight Polyethylene. Most common brand names, at least in the bow string industry, are Dyneema and Spectra. Comes in different grades or deniers. Original Fast Flight is 652 Spectra. Covers materials like Dynaflight '97, 8125, Mercury.
#3. HMPE/LCP blends. LCP is Liquid Crystal Polymer. The most common brand name in bowstring is Vectran. The characteristic that makes it desireable in a bow string is it's stability and resistance to changes with temperature extremes, especially heat. 452X has been the most popular on the other side of the sport for many years, and continues to be the benchmark, but other options are 450+, BCY-X (to be discontinued probably by the end of the year), and X-99.
Everyone has their preferances, opinions, and experiences. All the Olympic archers (actual Olympians...I say that because I've seen at least two "gurus" try to pass off "Olympic style" as actual Olympic archers) I know of (several) shoot 8125, as do many top archers. A few others I know that have been known to shoot pretty well (Rod Jenkins, Jason Westbrock, Denny Sturgis Jr.) do quite well with BCY-X. I'm thinking John Demmer is shooting BCY-X, but can't rememeber for sure. Of course it's the string material that make these guys such great shots!
I've had an obsession with strings and string materials for about 25 years now. The more I learn, the more I discover that there's tons more to learn. When I think I have something figured out it just leads to more questions, more experimenting, more time spent talking to archers and coaches and string makers, etc.
One thing is for sure. The string material is only one part of the equation. A good string can be made with the worst material, and a lousy string can be made with the best. Then you have to do your part with tuning, your release, silencer placement, etc. etc. etc.
Someone could spend literally years with a hooter shooter and chrony and test countless draw lengths, arrow weights, bow styles, etc. etc. etc and compile a book...and it's still not going to cover everything.
We do know that the "FF" type materials are more durable, more stable, more consistent. How much? Depends. That's my story and I'm sticking to it.