This is like the octane debate. Some say higher octane, premium gas, is a total waste of money. Regular gas is better on the wallet and the higher octane doesn't really improve your mileage or engine performance. It comes down to a matter of choice of the consumer. I, for one, use the higher octane on the premise it burns cleaner, gives a little extra boost in performance and helps keep the engine cleaner. I get 15 MPG with 87 and 18 MPG with 92. My choice. As to whether air is better than nitrogen it's the same. There are some advantages, whether small or imagined. As I've previously stated they use nitrogen on aircraft because it, supposedly, doesn't contain or hold water and it is non-combustible. If I owned a multi-million dollar plane, or any vehicle of that cost, I would go with the nitrogen as it is readily available in the industry. Why would I "cheap" out and used compressed air as even if you run it through dryers and separators you never get all the water out. So it all comes down to personal choice, cost and market availability. I would suppose if it were cheap & widely available I would use it, but until then I'll stick with air and deal with it's repercussions when they occur. Aloha!!