Some sorta-random thoughts on cotton vs. (synthetic) MF follow:
-cotton works great for buffing off wax (more bite than MF makes it nice for tough-to-buff LSPs) but only until it somehow causes marring. And unfortunately, IME that always happens sooner or later
-I think it was AI/ValueGard that once had magnified pix of what "very soft" 100% cotton did to previously marring-free paint, wasn't pretty
-conversely, at least in the sense that YMMV, somebody here once tested cotton and MF on a black Porsche and found that *his* cotton caused zero micromarring, no issues at all and it's not like nobody had perfect paint in the days before MF
-when the "MF removes too much LSP!" thing first came out (gee, it was my pals at TOL too, hate to :argue with Irene and her folks, but...) I did half-and-half experiments and found *ZERO* evidence that conventional/plush MF removed excess product. No diff in durability at all, for instance
-I use MF exclusively for buffing off polish/LSP residue these days, but I do use different *types* of MF including suede-style/low-nap, which sometimes works best for certain sealants
-for some situations I do still prefer cotton; e.g., when blowing water out of nooks and crannies I'll hold a cotton towel (stationary) nearby and blow the water into it. In cases like that, cotton simply soaks up the water better for me than MF does
-and I use cotton extensively when doing interiors. Also use it for the initial passes on really bad windows