I use several tanks. I have some Kanger MT3s, a Zen-Atty-Pro Genesis style rebuildable, and just recently aquired the Davide 3ml tank as well as a sister 2ml tank for my eGo. The Kanger and 2ml Davide tanks are great for on-the-go vaping, the Genesis is great for sitting around the house and I can switch out to the 3ml David on my Provari when I want to mix it up or don't want to worry about keeping my Provari upright - a requirement of the Genesis style tanks.
The Genesis style tank gives the best vape, but the bottom coil tanks provide a very, very good vape and are far more convenient. I like to rebuild my coils and do so with the Kanger coils and (obviously) the rebuildable Genny. I don't like top-coil setups, although many do. All in all, tanks are pretty cheap - with some exceptions (*cough* Zen-Atty *cough*). Try a few and see what you like. I can report the build quality of the new Davide tanks is top-notch.
Note that if you do decide on a rebuildable Genny, the AGT-T2 is a reasonably priced alternative to the Zen-Atty. (Although I love my Zen and make no excuses for it. It is a lovely piece of hardware.)