BCY-X is my favorite.
I started tinkering with it shortly after it came out and I love it. Bought a Samick Journey just to test it with (didn't want the bow to be a factor). The difference the string made (from a 16 strand Dacron) was nothing short of amazing. Even on this very cheap bow it's quiet, durable, stable, and consistent. I liked it so much that I took it to FL on a bowfishing trip (got my biggest stingray to date--around 80#), I used it opening day of archery season here (got a big doe), and I used it at the KY Tradfest in '14 to win the long shot novelty. Guys like Denny Sturgis Jr. and Rod Jenkins like it too.
If you liked 452X, I think you will like it. It's the next in line. Started with 450 Premium, then 450+, then 452X, and now BCY-X. As better raw materials become available, better bowstring becomes available.
8190F and Fury are supposed to be the same thing--SK90 Dyneema. 8190F has more colors and is cheaper.
Saw a guy somewhere else saying the rate of twist is different and that it made a big difference in the material. According to DSM (the manufacturer of Dyneema), BCY, and a couple of big name compound companies who all experimented with the rate of twist from very little to a whole bunch, that claim is not founded in fact. Practically no difference in performance between almost no twist and a whole bunch of twist. No idea why someone would think twisting would change the properties of the material.
8190F has gotten a good foothold in the market, even though it's only been out for a short time (released in late July). It's going to be a tiny bit faster (same diameter string) than BCY-X because it has no Vectran, and Vectran is heavier than Dyneema. I don't think it will be enough to notice on our bows, sinc X only has 17% Vectran. Probably no more than a couple of fps on a wheel bow.