This is something I was talking about on another thread; I do find that the MISTer can have wicking problems if it's set up the way it's supposed to be. i.e. wicks fully in channels. Opposite the review by Igetcha69, I find that this can be tricky to get working well, but when you do it's really great, and I use this more than anything else I have.
I'm sure cotton would work well. Personally, I'm too paranoid about burning so I stick with silica. But either way I agree that over filling the channels seems to be a problem. And I would suggest not having the wick in the channels too full as well as not having it too long.
It would be too hard to explain how I set mine up, maybe I'll take a picture when I get a chance, but basically I end up with four pieces of 2mm wick at the coil, so 8mm total, but less than 2mm of the wick, frayed up, going down the channels, and even then not going all the way to the bottom. Like this it wicks flawlessly, though I have had flooding if I lay it on its side when I have the juice control open a lot, but that's a relatively rare problem.