I only use mechs. Some are dual parallel battery mech boxes. I generally build pretty low, usually putting my power output somewhere in the vicinity of 100 watt, give or take 20.
I know exactly how I am going to build any RDA. The number of coils, the wire gauge, the number of wraps, etc. For whatever kind of build I feel like doing, I've done it enough times already to know almost precisely what kind of vape I am going to get and what resistance it will measure out to. I am very good at it and enjoy doing it this way. I get exactly the vape that I love. On occasion, I have done builds before that use over 200 watt. This isn't usually an all day vape, but I do it sometimes to take advantage of certain RDAs. With some lower gauge wire and something like a quad-coil build, it is quite easily doable. My wattage is infinite. There are no built-in limits.
I also like having mods that are elegant and durable. I enjoy maintaining my mechs. I prefer the way they look, feel, and function. Regulated mods are popular, and may take more of the market, especially for new vapers who are still trying to quit smoking and are uninterested in learning how to use gear. But mechs will never go away and will always appeal to the enthusiast market.