I just finished a Vintage Air installation on my '72 Cuda, which came from the factory without air. Except for a minor issue with the binary switch interfering with the grille, I had no problems with the installation. When I called them about the grille interference issue, they were prompt in sending me the necessary adapter. Their kit includes everything except for freon and 5/8" heater hose.
The things I liked about this kit as opposed to the classic air is that vintage supplies a new heater control panel that looks close to stock and bolts right in. The classic air has you modify the existing heater control panel to add switches in the back, replacing the cables (but it has the advantage of 100% stock appearing). Another advantage of the vintage air is that the lines from the condenser are all on the passenger side of the engine compartment, where the lines from the classic air condenser exit the driver side and have to route over to the passenger side.
It took quite a bit of time to get it all installed, but was well worth the effort. BTW, this thing sure does kick out the cold air, and I barely feel a difference in the engine when blasting this cold air ;-).