My friend, you do not need to be defensive. I've already said numerous times now to try natural gut. Yes, it is expensive, and if you don't have a stringer, it's the best performance value. Kevlar may last and last, but if you're not breaking poly, then I see no reason to switch from it to something more uncomfortable.
As far as breakage goes, I have 3 frames waiting to be done: a kblade 98 with popped RPM blast, another blade 98 (this past generation) with popped full ALU and a microgel radical with popped SPPP. These are all players I hit with on our club team. Heck, I used to string for one of my professors, and he and his daughter would pop full Big Ace every few weeks. Breaking poly is not that unusual. The only point that I'm trying to make is that if you're not breaking it after 100 hours, then it's not the best string type for you. The added spin is gone after that first 8-10 hours once the string is dead.
edit: my defensive comment does not apply, I started writing this post this afternoon and just now finished it haha