HastyP, the A430 is a descent double action AB for the price. Like others have said, it comes with fewer tips, four I believe. It does not have the same ergonomic feel as the 470 , but it atomizes the spray as well as the 470. A nice AB altogether.
As far as the air supply goes, try to steer clear of tankless compressors. The Testors Blue Mini is such. Without an airtank you're going to experience a pulsing effect caused from the motor which carries to the sprayed paint. This effect will really be apparent in close-in detail work. From what I found the Blue Mini sells for about $100.
If I were you, I'd look at something like the one below from Coleman. It's small, has a sufficient tank, and costs only about $20 more. It even come with a regulator, and it shuts off when the tank is full, so you can paint in silence.

Well worth the twenty more dollars.
Model: VP0000201