Unless one wants to puff vapor like "an old train's chimney" (I'm serious..), 5Volts will be more than enough.. I used to smoke hookah at least once or twice a week. Trust me, 5volts with 2.4ohm atomizer will produce as much smoke as a hot fruit-head of hookah molasses!
Now, does the VAMO have an upgradabe firmware? nope.. A monitoring software? nope! As good customer service as the eVic or MiD ? Of course not. Reliable, true, manufacturer's warranty? Nope, unless you send it back to China and hope it comes back.
If you decide to get the eVic, get it from Ovale USA.. They picked up on my first call when I entered the wrong shipping address and changed it immediately. Warranty is guaranteed on any manufacturer defects. That applies to the Janty MiD too.
Now let's compare aesthetics/looks!
The eVic: I see a classy design, a nice screen, two different kinds of threading (attach double the accessories!)
The Janty MiD: I see a good looking "Personal Vaporizer", I wouldn't be afraid to pull this out after dinner at a nice restaurant, an airport, or during break from a meeting at work.
The VAMO: Looks cheap, poorly designed, and frankly embarrassing to walk around with.
I'm glad The Ocelot brought up the MiD, it's a nice PV too. Pick either the eVic or MiD