It's all a product of wattage. Vapor production is greater the more VG you have in your juice. Increasing the voltage will increase atomization of any juice, but you quickly reach a point where more heat equals burnt taste and lower atomizer coil life. Some atomizers utilize coil arrangements that provide better contact with the juice. I like Boge 2.0 cartos and stainless steel 1.6 ohm dual coils. Smoketech is one brand of SS DC carto that's popular, but most are good. Read the reviews for first hand info.
Dual coil (DC) cartos are a good choice. An ecig is just a battery with an atomizer attached. Most people don't use the ones that come with the ecig. They move to cartos, tanks, and drip tips.
A more pointed question would be "Which atomizer/battery combination produces the best vapor?". After that, the choice of juices comes into play.