Wattage really doesn't mean anything without the other factors taken into consideration. Wattage is not heat, it's electricity. A better question would be "what temperature is the best to vape?" -- and even then there's still a range of answers depending on personal preference (although for temperature there is a definitive "don't go higher than this").
1 watt = 1 joule per second (this is power).
1 joule is a quantity of energy.
The way I understand it with regard to vaping (heating liquid), watts = an
amount of heat per second (not temperature).
If we apply 1 watt to a wire that has a surface area of 1 square mm we have a watt density of 1 watt per square mm. This concept is known as heat flux. If we submerge the wire in juice that heats up, boils and takes the heat away with it the wire will reach a stable temperature and there will be X amount of vapor produced.
If we double the watts and thus the heat flux to 2, assuming enough air flow and wicking speed is available for the higher power, there will be an increase in wire temperature but the majority of the extra heat will be used up by the juice vaporizing faster.
Once the wire becomes dry its temperature skyrockets because there is no juice vaporizing and taking the heat away.
So, if we're talking about wire temperatures heat flux is in my opinion the most critical single factor.
OTOH, neither watts, heat flux, heat capacity, wire gauge, resistance, air flow or atty design taken on their own defines the vape, though all of these are limiting factors. For example, you can't use 20 gauge wire in a high air flow atty at 6 watts. They all work together and need to be appropriate or the vape will not be the best it can be.
