Cotton is grown in several countries and processed in several factories. Quality differs. The ones i bought locally have been crap for vaping (clean eco brands, both pads and balls) and they have also differ in taste. Some have been fine to taste, but shrunk to much to be usable. And some have had a real bad taste. Also difference in how well they transport fluid.

But that is also true for vaping brands. Got Kendo vape cotton at one point, think it was the gold one. Tasted like an old sports bag for several refills.

What we can know is that there most likely isn't a single vaping brand that is not just a repacked cotton that is used in some other fashion as well.

I also got a kg of hemp fibers from a manufacturer at a point. Very nice wicking properties, but had a earthy taste... works fine for tobacco juices as it kinda complements it.

What is also true is that the ability to taste differs from person to person. I have a very sensitive taste system and am probably a supertaster. (science suggest that 25% are nontasters, 50% medium tasters and 25% supertaster) (i do think that its more to it than that though, would probably find even more diversity like, nontaster, lesstaster, mediumtaster, moretaster, supertaster, superdupertaster and so on) So individuality matters.