Mostly in my honest opinion the variable watts is just a way to get some extra price from a mod.
Don't get me wrong, there are times when the function of the mod which adjusts the amount of volts going to your atomizer/carto/whatever to a preset amount of watts is going to make your life easier, like when you start your vaping and have found out through trial and error your very own "sweet spot" to which you want to adjust your mod.
But as time goes on and you start using numerous vapourizers, say different coil cartomizers, clearos and rba's you find out that the amount of power needs to be adjusted according to the current device you are using.
So I would go with a Provari and a fully mechanical mod with a Kick to cover all the bases.
Don't get me wrong, there are times when the function of the mod which adjusts the amount of volts going to your atomizer/carto/whatever to a preset amount of watts is going to make your life easier, like when you start your vaping and have found out through trial and error your very own "sweet spot" to which you want to adjust your mod.
But as time goes on and you start using numerous vapourizers, say different coil cartomizers, clearos and rba's you find out that the amount of power needs to be adjusted according to the current device you are using.
So I would go with a Provari and a fully mechanical mod with a Kick to cover all the bases.