I agree with the idea that both the Air 2 and conventional octo arguments have merit and that both are ideal under differing circumstances.
yknot:
I also pointed out that octos very rarely funtion for the benefit of you as a diver but rather for the use of your out of air buddy. I also pointed out that a truly out of air diver isn't likely to grab your inflator hose.
I agree with you on this as he will most certainly not grab for your inflator hose. But he also will not go for your octo either.
The fact is that in most recreational situations the average semi panicky diver in a truly out of air situation will go for the reg in your mouth since he can see it, he knows where to find it, and he knows it works. Murphy's law dictates he will mug you for it right after you exhale so being able to find your octo in a hurry and being sure it will work becomes important, particularly if the OOA diver is totally panicked and immediately starts clawing their way to the surface.
In my opinion, there is a real advantage to having an Air 2 in that situation as it is always at hand and I have never seen one filled with silt, sand etc, as their use as the inflator keeps them flushed and ready for use. I cannot say the same for the standard octo.
Where an Air 2 is at a disadvantage is for a technical diver who may have to swim along the bottom, out of a cave, wreck, etc, rather than make an immediate ascent to the surface. In that situation a normal octo allowing more head movement is beneficial. But I also need to point out in that situation the diver will be donating the primary reg, normally on a 7' hose, to the OOA diver and using a conventional second stage on a normal 22 to 26" hose himself. Putting the diver on the long hose makes it much easier for both divers to swim normally.
In a recreational situation it would be preferable to have the OOA diver on the longer 40" octo hose, but it usually does not work that way. A 40" primary hose does not route well, sticks out way too much, and is uncomfortable as it tries to push the reg to the left. So unless you can switch after the OOA diver calms a bit, you will be stuck face to face with the OOA diver using your primary on the end of a 22" to 26" hose. In that case, you might as well have an Air 2.
For this reason alone however, I predict that within 5 to 10 years, a long hose (5' to 7') primary second stage will be standard equipment for recreational divers as will the concept of donating the primary reg to an OOA diver. At that point, an Air 2 will be hard to justify as it will offer little advantage over a long hose primnary/short hose octo arrangement. I have not yet met a diver who tried a long hose primary second stage in realistic conditions that did not like it and the only thing preventing the change in at the recreational level is institutional inertia from instructors and agencies who still teach and promote the current methods of donating an octo on a 40" hose.
In short, despite current recreational training practices, I can think of few real life situations where the OOA diver is the one using the octo. So the moral of the story is to buy a very good quality octo and keep it well maintained as it will be in your mouth, not the other diver's.