I've heard people talk about PVs with ceramic wicks, what's the story with this?
Here you go. These are the big dogs. These are what most experienced drippers end up using as they are above and beyond anything else even close.
http://www.e-cigarette-forum.com/forum/atomizer-reviews/280261-ava-made-usa-49-95-atomizers.html
Actually, that's neither what most drippers use nor is it what is being referred to here. I'd say right now, the old standby for drippers is the 306 with the io6 and HH357 gaining on it. There are a few people out there using the AVAs but, I'd say not near as many as are using other devices.
I'm not saying it's a bad device. I've been considering one myself. However, as I understand it, this one uses a solid porous piece of ceramic. It's not a wick in the usual sense. For me that's interesting and it could be very durable. It's pricey but, it might be worth it if it has a really long life.
As for what the OP is talking about. Inside an atomizer there is a wick that the coil is wrapped around. It serves to supply juice to the coil as the atomizer is firing. It's not a radiator as in a heater. Most commercial atomizers use fiberglass string for the wick material. Where the debate comes in is when you bring rebuildable atomizers into the mix. There you have your choice of wicking material. The main options being debated are fiberglass, silica, stainless steel mesh and ceramic. In this case, the fiberglass, silica, and ceramic are in the form of rope or string.