Dripping can be done on almost any PV type.
If you have KR808D-1 batteries, then use a 901 atomizer, or pull the poly-fill out of a cartomizer.
Of course there are many variations of 510 threaded atomizers.
The other odd platforms usually have a native dripping/cartridge atomizer of some sort.
For a 510 it works something like this:
Drip about 5 drops on the bridge (little metal screen over the coils). Give it two quick burns without drawing air, then add 2 or 3 more drops. Now you have the option of vaping that load out (about like having a tobacco ciggy break), or you can add a drop every now and then to keep the screen wet for continuious vaping.
Yes, this approach is more true to the juice flavorful than a cartridge or cartomizer. The main reason it is more flavorful is that the coil is truly wet. Where with any system that uses polyfill or wicks...it has to be able to feed juice to the coils and keep them wet, and so far there just aren't any options that can soak up and feed the juice that quickly; hence, less vapor and less flavor.
I never was able to get the Ego-T to perform very well, but others have come to swear by them.
The closest to direct dripping I have found using a Cartomizer are the CE2 and Vortex designs.
They use silica wicks suspended in a tank of fluid to keep the atomizer coils wet. They do their job fairly well out of the box, and very well with some minor modding.
These work very well in my opinion, but so far, every wick based carto I have ever tried does require some tweaking for optimal performance with various juices. No two juices are exactly the same in viscosity...where one will leak through the tineiest crack, another might be so thick that it just clings to a wick or gets caught in the spaces around the wick designed to prevent carto leakage.
FLüXomizer CE2 Cartomizers - GotVapes.com
GotVapes VORTEX 808 Bottom Coil Clearomizer - 1.2ml 2.7ohm 5PK [gotvapes-808vortex-2.7ohm] - $12.95 : GotVapes.com, E-cigarette Supplies - Atomizers Cartomizers Mods Juice and more