Good question. Most people who prefer mechanicals like that the amperage is limited to what the battery can dump out. This makes possible some truly unholy setups with multiple coils and sub ohm resistance that a vv / vw can't handle. Sorry i'm on my phone at the moment and can't give you a direct link right now, but do a YouTube search for "dodeca coils" and watch the first result. That sort of beast is only possible on a mechanical.
Personally, I prefer mechanicals because they are much more efficient for the size. I owned a ProVari at one time. It was a great vape, but it was like vaping on a mag lite. Vamo, Zmax, etc are even bulkier.... Unless you get a mini, but that would mean switching out an 18350 every 2 or 3 hours. Minis also usually have the firing button directly in the middle, which forces some carpal-tunnel inducing grips. Even if you prefer the consistent power of a vw device, a kicked mech will be smaller and friendlier to your grip than an electronic.
Super-T Manufacturing has what I think are the best, most electrically efficient mechanicals.
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