tibby

Hi Ben,
As others suggested above the key is to read as much as you can on the subject before making a choice. A good start is Mastering Rebreathers by Jeff Bozanic and articles here on Rebreather World. A rebreather experience helps but don't let yourself mesmerized or discoureaged by the first unit you try.
If you haven't yet, I strongly suggest you take an Advanced Nitrox class, it'll be a huge help in understanding what you're buying.
Good luck,
Tibby

__________________
Does the voice of reason change when you add helium to the mix?...hmm