For durability and reliability NOTHING beats a mech mod.
You could take a copper Nemesis, bury it in the dirt, leave it for 1,000 years, dig it up, clean it off, toss a battery in it and it would work. I doubt you could do the same with a Provari.
And before you say mech mods aren't regulated, they most definitely can be.
Tell that to the mech mods I own. They are all authentic, before that becomes an issue. Every single time I change a battery I reliably have to futz with the switch to adjust for battery rattle and contact. Last time I checked, when I change the battery in my ProVari I reliably start vaping.
And sure, you CAN make a mech VV but now you have yet another piece of hardware that can fail. Bury that Kick for 1,000 years and let me know what happens.
Like it or not, a ProVari is hands down the cheapest, most durable, longest lasting, most trustworthy VV device you can buy today.