Out of all the RDA's I've tried, the Vicious Ant Cyclone AFC is the best in terms of flavor. It is a very small atomizer, and due to it's small size, a single coil produces intense flavor (Very small chamber).
Pros: Flavor; Single Coil is usually sufficient; Built with 304 Stainless Steel; Adjustable airflow (Two adjustable slots); Single coil or dual coil airflow; Looks awesome on a Provari Mini
Negatives: Not a heavy cloud producer (I'm not a sub-ohm vaper anyways, but if you are looking for clouds, there are better choices); The small size of the atomizer does not allow many build types (I usually use twisted 30 gauge), but if your looking to build Clapton Coils or the similar, there are better choices; Small allen screws and allen key (I replaced my screws with M2x4; Cost was like 0.16 a piece); Not an adjustable 510 connection (However I've never really felt it needed adjustment; Looks almost flush on the Provari Mini).

Close up view on a Provari Mini

Next to a Yaeliq (On the right);
Much smaller than typical

Twisted 30 gauge (Ekowool);
Dark color of wick from Belgian Cocoa