Wow! my first post and all this. My girlfriend and I learned the air2 system, and were quite comfortable with it. But, I've been to a few dive shops, and encountered many configurations. I fully understand the importance of a backup reg. But how many drownings resulted from a diver sucking his bottle dry? Many from what I've read. Yes I am a newbie, and yes I went P.A.D.I. and no I'm not a risk taker. Safety is a big part of my life, from my job especially, to my homelife. We have a pool to practice, and I do plan on fine tuning our skills as much as possible.I do not think I will have a need for a pony bottle, but I do like the idea of having a totally seperate air supply.As far as the air2, if someone grabs my primary, I know where my backup is.