I love using KGD. I can taste a big difference between Rayon & cotton, but not really between different cottons.
For me, it's about convenience. I can pre-cut a bag full of about 4mm wide strips, and it's so consistent in being the perfect amount for a 2mm ID coil. Beats the hell out of pulling apart pieces of cotton bacon or rayon, trying to consistently get the exact amount needed. And I know some people peel the outer layer off, but I never have, and have never had wicking issues doing it that way.
I am surprised vape shops don't carry it, as well as Muji, rayon, and others though. It's not like it has a shelf life, and seems people would pay a really nice markup for such a cheap item, while they were in the store.