Imagine - on normal air your bottom time is about 25 minutes on the Rainbow Warrior - but using Nitrox you have twice as long! You will also find that you will start to explore sites not normally dived by others. Reef systems in the 20-30m range would have great benefits on diving on enriched air Nitrox.
This is NOT a technical deep diving gas! Simply put, it reduces the amount of nitrogen (replaced by O2 ) in your breathing mix. This makes your body think that you are diving to a shallower depth, thus being able to spend longer underwater safely.
THAT'S IT!! A MUST DO course!