I've yet to be able to taste the difference between cotton and silica (or even silica and SS) most likely due to the abuse of my poor taste buds over the last quarter century (I still need extra flavor shots in my juice to get good flavor).
That said, what I like about cotton is that it is so easy to re-wick (especially micro-coils...I've yet to make a decent micro-coil with silica...it just doesn't play nice). A cotton wick will last me three or four days (very dependent on juice...some folks re-wick every day...RMMV) and it takes just a minute or two to throw in a new one. This means the awesome coil I perfected doesn't get tossed in the trash as soon as the wick goes bad (although silica IS very easy to keep clean and will last quite awhile...a month or so on most of my builds).
For best results, less cotton is more. A little goes a long way. If I use too much cotton I can definitely taste the difference. If you have been nonplussed by cotton try using a little less. Makes a big difference.
And now for the obligatory gratuitous self-promotion.
My first micro-coil. 10ish wraps of 30awg Kanthal (using a 16 gauge needle) for 1.5 ohms on my Reomizer...absolute heaven.