ProVari isn't so much watt limited as it is amp limited. It has a fairly conservative current limit, and with the v2 electronics (also used in the 2.5) it's a little bit higher... 3 amps maybe? I think it does reach 15W, or high 14's...
That's all part of the safety circuit...
IMO, mechanicals aren't worth a crap for standard atomizers / cartomizers... You could use a kick, but that has a 10W hard limit. So I use a provari for that stuff
Where the Mechanical mod really shines is with Genesis style atomizers. Stainless Steel wicks, and low resistance coils.
The flavor you get is very clean, with a lot of vapor... The higher you get out of the sweet spot with a cloth wicked system, the more muted or burnt the flavor becomes...
So, using a low resistance genesis with a mechanical allows for a flavorful, warm vape. And as suggested you don't have to hit it very long.
It's much more comparable to smoking an actual cigarette, albeit with better flavor! Short drags, and a little bit of heat. I love it
So for my genesis atty's, mechanicals are the only way to go... For my cartos and cloth wicked devices, I use VV/VW devices around 8-10 watts.