Recently picked up the Kobalt portable air tank so I could run a brad nailer to do some finish work in a bedroom on opposite side of the house from the garage. House full of kids and a newborn so I didn't want to run air lines across the house nor did I want compressor noise from a pancake compressor in the house - the goal is all that dirt and noise can stay in the garage.
Most of the portable tanks I saw looked good but come with really chintzy fill valves / manifolds that reviewers unanimously said needed to be replaced with something better. The Kobalt on the other hand has a really sturdy metal manifold and for the inlet has the standard Schrader valve AND a standard male quick disconnect behind a check valve - meaning you can fill this from your air line super easily or use this to add some volume to your compressor as a satellite tank.
It comes with a standard female quick disconnect for the outlet - which I took off so I could add the small air regulator I spoke about in my previous thread. It also has a standard drain valve on the bottom, simple and easy. I've been very happy with this setup so far.
Here's the links