Just in my limited experience, a properly setup Genny will equal or surpass a properly setup RDA, followed by an RTA, depending on design.
So that's kind of a non-answer.
A LOT of it has to do with your build, the air flow, power settings, and chamber size. For example, I own a Lemo and a Lemo Drop. With the same exact build, same power, same air flow, I get the same flavor experience because it's got a small chamber.
More airflow better taste?
Not necessarily. Think of it, in a roundabout way, as an air/fuel mixture in a car. The flavor is the gasoline, the air is... well, the air.
If you add more air, in order to get the same percentage of flavor, you'll need to produce more vapor to compensate.
Or, another way, it's like mixing a batch of lemonade. If you add more water, it will dilute the flavor, so you'll need more lemons and sugar to compensate.