I tried most of the Japanese cottons available over the last year or so, and really didn't notice that much difference.
It's really all about how they wick, since ideally you shouldn't be burning them, their inherent flavor shouldn't matter. .
That being said- I switched over to Egyptian Cotton (Drago Premium Cotton) about six months ago after trying a small piece at a Vape convention and I haven't gone back to Japanese cotton since.
Since it's 100% organic and unprocessed, it's not as pretty as the Japanese cotton, and its got a few seeds that you have to remove sometimes (they are TINY!!), but it wicks so well that it's worth it...none of the Japanese cottons even come close. The flavor is completely neutral, and very burn-resistant unless you run it almost dry .
JMHO...