Not everyone wants a VV mod... I know for me, I adjust my atty resistance to suit my voltage... rather than vice versa. I've found perfect attys for 3.7v/6v. If I were to spring for a Reo, it would be for the bottom-feeding... and let me say that this option looks better and better each day, although I'm 100% satisfied with my Prodigy.
I prefer mechanical devices... the more simple the better... much more reliable. If you have good batteries, a good atty, juice, and clean contact points... you're in business! When using a VV mod, you introduce a whole bunch of new wires and circuitry (points of failure).
If a resistor blows that costs $.50, could you or the average vaper repair/solder it? Or would your mod go down until you could send it off to have it fixed? Would your vendor fix it for free, or would you have to pay?
Jusy my thought process. The only thing thats slightly-intriguing about VV is the fact that the same juice in the same atty will taste different at different voltages... but if my juice already tastes great, I've decided that's not important to me.
Just my $.02 : )