Before going for the Dna20D think twice. It's longer than the regular VV.
It has many features and advantages, but it does have a drawback
according to the website
" It features controlled power from 7 to 20 watts" and the minimum Ohm for the atomizer is 1.0 Ohm
Below is the link to the Data Sheet.
http://evolvapor.com/wp-content/uploads/dna20.pdf
I'm currently vaping
.7Ohm at 4.20Volts or 25 Watts
So my regular vv is more of a performance machine than the Dna20D. I wouldn't be able to vape .7Ohm on the DNA20D. Otherwise it looks awesome. As long as you are Ok with the 1ohm limitation along with 20 watt limitation it looks like a fantastic module.
On the other side of the coin, the Dna20D accepts 18650 Batteries and this will give you much longer lifespan than my stacked box. I change batteries at least twice a day. 25 Watt Vaping does take it's toll on batteries!!!
I'm not stressing anymore I have 4 sets of batteries and just bought an Xtar WP6 6 battery charger so the battery issue is mute!