Actually they are. That's been confirmed by a number of independent
reviews of the new vv/vw devices. Which is one of the reasons they've taken off. The Provari is the most accurate on variable voltage, but many of the vv/vw devices are so close that in practical terms there is no difference in terms of accuracy for the vaper.
With accuracy the game has lifted. That's happened just within the last 6 months or less, and I think seeing that accuracy on the vv/vw mods has been partly what has prompted so much interest from people in wanting to see a Provari vw. Whether they will bring one out or not at some point is anyones guess. For the moment they aren't planning to.
I haven't seen any side by side test comparisons between the vv/vw mods and
dna mods so don't know if the
dna performs any better - it has smaller increments for those who want that. My understanding is the DNA20 has a 4 volt minimum, and SR is recommended. That could be an issue for those wanting lower ohms on their rebuildables.
That's not an issue with the Provari, or with the better vv/vw mods. The Provari has I believe the best capacity for very low ohms - like 1.0 or 0.9 ohms. Unless a mechanical mod is used.