I did my AOW and Rescue classes earlier this summer, and was getting bad headaches from breathing very dry air, my throat was killing, etc. I emailed Joe, and he said that the Apollo reg had made him enjoy diving again, so I figured it would be worth a try. I bought one that night, and have used it ever since, have never had any problems, and my dad even did his OW checkout dives using my reg, just so he could see how well it works. He is now looking to buy one as well, because he liked it so much. A great buy, highly recommended. The fill valve works perfectly, and allows you to make multiple dives without breaking down the device between dives.