I use an airflow controller with my Protanks and Davides ... it works really well, and I only need one per device (I'm lazy and don't want to move it from device to device), but you could get away with just one of these. There is no reason to pay the extra to have it built into the
tank if all you want is the airflow control. If you are looking to try other/new tank options, that is a different matter, and the Aerotank and Nautilus are the only 2 I know of currently, but watch for more as the year goes on.
As always ... YMMV!