I know it's obvious, but the best tank is the one that works for you. I'm currently really enjoying the Aspire Nautilus Mini with the BVC (bottom vertical coil). Adjustable airflow, good vape at anywhere from 6-11 watts- and the atomizers last well. I'm thinking of getting a regular Nautilus tank for the larger juice capacity and use of the same coil, but that's no big deal.
After 6 years of vaping, I'm pretty middle of the road- I'm not into "huge clouds" that you can get from sub-ohm tanks, but some folks are. These make plenty of vapor without fogging the whole room like sub-ohms can do. If you're just hunting around to get off of cartridges, you could do worse than to go with a nautilus/bvc. YMMV ;-)
