I'd recommend going with a 120v fan. The cab is already wired for it, all you have to do is tap into the existing wiring for the fan. That power is fused and separate from any of the game logic circuits. If you tap into your AR2 or game board, you are asking for trouble if the fan siezes up or fails.
Just my opinion here, 12v fans are cheaper and easier to find, but I chose to go 120v to keep it isolated from the game board circuit.