Now as far as John's Customs strings....Over the years I've shot A LOT of strings from A LOT of builders...From small builders at local shops to the big guys like Winners Choice & Vapor Trail..I started shooting John's strings back in 2008 and have been with him ever since. IMHO he builds the best you can get, he's very precise on his lengths, he stretches everything so there's no creep and his serving is second to none...Serving quality and precise lengths are what seperates the good builders from the great builders. As far as the 8190 material goes, I've shot it on a few bows since the 8190 hit the market and I really like it...Very little stretch in it, a lot like 452x, but it fuzzs less than 452x...So with less fuzz you don't have to wax it as much, less wax equals less build up in/on the strings...Excessive wax adds weight to the string so you lose performance over time and wax holds dirt and that leads to strings that look nasty over time and can also lead to more wear on the strings with all the dirt that gets in them. I've shot most all of the string materials on the market, I've been happy with 8190 so far...John really likes it too, he gets less stretch out of it and better speeds.