Doge V2 - Airflow (2mm x 11mm air slots), chuff cap, and 3mm post holes makes for fat clouds with fat wire (capable of holding 16AWG wire).
MutationX V2 - Airflow (18 holes of air, WHAT?!), ease of building (center post block for dual / quad builds), and post hole sizes to accommodate up to 20AWG wire.
Plumeveil V2 - Airflow from all directions (top, bottom, and middle!), ease of build (center post block - see above), post hole sizes to accommodate up to 20AWG wire, and finally flavor. If you're not so into flavor, then the above 2 would be for you.
-OR-
Mephisto V1 or V2 - If a Plumeveil is something you might not be interested in, please - do indeed look into the Mephisto V1 or V2. I think the original Mephisto RDA was innovative to say the least. As it pumped out some fat ... clouds, great flavor, but sported the 3mm holes in the posts which is where Congrevape got their idea for the Doge V2. The airflow design on the Mephisto V1 was 2mm x 5mm (I think) and the Mephisto V2 has the same 2mm x 5mm Cyclops airflow setup with 3 holes just below that for even MORE airflow. So I mean, it's personal preference there.