I've tried a couple different wick materials now and here's what I have found,
Silica: wicks well, damn near impossible to scorch, can be dry burnt, ideal from dripping if your constantly changing flavours, pain in the ... to build with as you pretty much have to build your coils around the silica.
... cotton: wicks quickly, easy to re wick with, good flavour cheap as chips, good all rounder, gives you a warning taste before you scorch it.
Rayon: wicks super fast, pretty much the same for flavour as ... cotton, easy to work with and re wick, horrible if you get a dry hit. Also very cheap to buy
I use rayon on my rta's where I'm vaping one flavour all day and silica in my magma for testing my diy fluids