In my close to 3 years of vaping, I have never came close to any wick I like better than XC-116. It wicks like no tomorrow, retains good flavor, is very durable, and is just plain good..

I use it in just about everything I have. Some may say it's not proven safe, but unless folks are getting manufacturer specs on the fiber diameter of the silica they're using, anything below 6 microns could be an inhalation hazard with that.
Just make sure to get the kiln-treated stuff, and give it a torch for good measure. I have some ekowool, and IMO, it's not as good. When I do use use silica, it is the German silica. It has a 6 micron fiber diameter, and gives me just about the same flavor as the XC-116. Next up would be the Nextel XS. (The difference is XS is silica, and XC ceramic) I've never tried the XC-116 over SS rope in a genny. I used to use 500 SS mesh.. I haven't used it in awhile though since I kept finding charred black particles in my top cap using the mesh. I've yet to see anything like that with the XC-116 when I use that alone as a U wick in a genny.
Also, the trick with XC-116 is to wrap the wire just tight enough to make contact with the wick.
Just my

.. I'm sure many other opinions will be along soon..

I'm speaking of the XC-116 in general since I use it primarily in the Terminator C, Kayfun-style with a conversion kit for the Term C, stand-alone U wick in my gennys with no mesh or SS rope at all, and recently the Hercules.