I have the unpopular answer.
Tried Halo, gave it away, I kept breaking that stuff trying to get it as tight as I want, Angle Majesty is over rated in my book. Don't like it, and it is the stock stuff on the strings that come on the Matrix strings, we have all heard of the issues! I like Brownell, and BCY crossbow serving material, and Brownell RCT in .036" Wish they offered more colors, but so far black only. That stuff bites down hard, and never slips! It grabs on in the back serve so well, you have to lube it up, or it will be a tough to pull it home.
My opinion, and preference.