I have the Vintage Air set up on my 1962 C10. It came with three vents, one for the each corner of the dash and one for the center. They blend in well and provide plenty of airflow.
The controls use the original factory controls, and the main unit replaces the factory heater/defroster unit. As was stated earlier, I lost part of the glovebox, but that is a small and acceptable trade off.
I'm pleased with the Vintage Air Unit.
Originally, I ordered the Old Air unit for my 1962 C10. When it came in, I took one look at the vents and determined that it would never work in my truck. They were too large and interfered with the operation of the emergency brake on the driver's side of the cab. It might work for others, but for my truck it was no dice.