I switched to Nitrox a few years ago and I love it. I was using FO2 and was tired at the end of the day. With Nitrox I can make 2-2tank dives morning and afternoon and still make the night dive and not be exhausted at the end of the day. Wife and I both use Nitrox and have greatly increased our bottom times on dives less than 70 or 80 ft.