Ok, this is what I know. Winners Choice strings are pre stretched before assembly. This is better because each strand is stretched identical, whereas if you stretch an assembled string, you cant guarentee that all strands where stretched the same. Thats what makes them better.
A WC rep told me that this is one of the main reasons why your peep rotates so much. One strand stretching a little farther then the next. Makes sense.

As for Muzzy strings. Maybe I got a bad set, but the I really am huffed about them right now. The servings are already starting to seperate a tad around the cams and it was twisting like a Kansas tornado when I first put it on. I put a ton of twist in to remedy it, but had to take some out to get my draw length right.
All and all, I am not impressed with Muzzy strings. My next set will be Winners Choice.

Just my thoughts on the matter.