I'm going to revise my earlier statement. Another very low-maintenance vape is to use the Smoktech eGo dual coil Mega cartomizers.
These are the eGo-threaded ones. They advertise them as holding 5 ml of liquid; I can't usually get more than 3.5-4 ml into them but they produce a lot of vapor and a lot of flavor, very close to a cartotank without any of the spillage risk or mess. With that much juice they last a decent time before needing to be topped off and can be topped off more than a regular cartomizer.
I have to agree with this. After trying all kinds of things from 510 atomizers & cartridges, regular & XL cartomizers, several kinds of CE-type clearomizers, vivi-novas, and carto tanks, I've settled on the eGo Mega Dual Coil Cartomizers on an eGo-style battery (either fixed or variable voltage) for most of my vaping. They are cheap, no-fuss, easy to fill, don't leak, give me plenty of flavor & vapor, and are "pocket-friendly." I keep one of these setups on me any time I'm out of the house.
Second place for me goes to the carto-tanks. I have several from Fasttech that I use Boge LR prepunched cartos in on my VAMO when I'm in the house. They have all the same good attributes as the EMDCCs except I don't trust them in my pocket. Occasionally I'll use one on an eGo battery in the truck, though.
Dave