FYI, If voltage is a really big factor I am also considering a Lavatube.
As for the lavatube, add a little cash if you can and get a decent VV model like the BuzzPro. IMO, the LT is a terrible device. It won't hold it's voltage for the type of hardware you put on it.
The KGO meter higher in voltage than other batteries. Something like 4V under load for standard resistance. If you compare it to an eGo, the KGO will kick it in the britches. Nicer vapor, flavor, TH...and warmer vapor.
I agree with hairball. I wouldn't want to deal with the lavatubes limitations.
A better battery model such as the Kgo over your smoov is not just that you will get longer battery run times. As batteries discharge, they are not able to provide peak power to the atty so the last half of your batter charge will not be as good, power-wise or vape-wise as the first half. The higher the mAh of the battery, the longer it stays near peak performance. So you have better performance longer.
If I was going to get a budget VV model, I would look at the new EVO. I've never used one, but from what I have read, they can use any atty/carto, including dual coil cartos without a drop in power like the lavatube. It has the three major power settings of 3.7v, 4.5v and 5.0v. I would look into it over the lavatube:
EVO V2 Kit
And if you don't want to go VV but want better TH, then get a good 5 volt model PV.