FC-2000 Slotted vs. Round Show Down - Results
Ok, I have the slotted version broken in. They both vape well, with some slight differences. The only preferred benefit of the channel is that it is 1/2 pull faster to produce vapor from a cold start. Probably due to the exposed wire heating and reaching vape temp faster. The trade off here is increase throat hit from the wire. The round wick vapes perfectly smooth, with a slight TH from the Nic in the juice. The slotted wick while not bad, has a tinge of the harsher TH you get with a loose coil.
The other benefit of the slotted wick depends upon your wick hole. You need space around the wick in the wick hole for optimal juice delivery. So the choice is either a looser fitting round wick or a tight fitting slotted wick. Same effect. So for example, a 1/8 slotted wick may perform the same as 7/64 round wick in a 1/8 hole. You get the point.
Obviously the slotted wick has less overall mass, so their is less heat sink, etc...but I did not see any loss of juice delivery with less mass, so the theory that ceramic carries additional juice on the outside surface area makes sense.
I tested these side by side at 10, 12 and 14 watts on a Provari and Sigelei Z-max. I switch the attys back and forth, to eliminate any PV related factors.
So with these two atties set up with 30g at 1.4/1.5 ohms, I think the slotted wick has a slight edge really only because of the faster start-up time. The wire gap hot spot issue is not as significant as I thought it would be (It may be for others). (A more optimal set-up for round ceramic would be to have a clear .3-5mm of space between the wick and wick hole, Mine was tighter.
One final note: When I compare both of these to a 3/32" round ceramic with ribbon on the Cobra at ~.9ohm, they both are inferior by a wide margin. However, this is not really a fair comparison because of the different setups. Just my

Hope this helps.