I have several Smoktech DCT tanks, so I've almost always used the Smoktech brand. I've recently gotten some shorter tanks, and have tried Boges, which are of course single coils. The only difference I've found is in the polyfill. Boges seems to be denser and slower to absorb juice.
I had not been entirely happy with the dual coil Smoktechs. I have had issues with sliding my self-punched cartos thru the Smoktech endcaps. A side effect of self punching can cause distortion of the carto's roundness to the point where it catches or binds where the hole was made. I decided to try pre-punched cartos.
I had also recently read that dual coils don't effectively fire unless the wattage fed them is at least 4.5v. Since I am using 3.4v devices, I decided to give single coil cartos a whirl.
I got some 2 oHm one and two hole prepunched Smoktechs.
Single Coil XL Tank Cartomizer for the SmokTank XL
I'm glad I tried these. These just seem to work so much better for me than the dual coils. Plenty of vapor. Better flavor, at least initially. I use the single holed for thinner juices, and the double holed for thicker. So far they are working very nicely. Only exception is the tank with Boba's in it isn't wicking enough despite two pre-punched holes. I'm not sure if you can even use Boba's in a tank its so darn thick.