Just put a set of SX2 on my Insanity. I've only had them on for a couple days, but I'm just an average hunter/shooter who like to get the best I can. I will say that I have noticed no serving seperation or stretching so far, but I've had almost a doz. sets made with 452X and I can't tell any difference in the look, quality. speed, or quietness of the strings. I would be just as happy with either the Brownell's (XS2) or a set made from BCY (452X)