Well generally you will have an octo detuned so that it doesn't freeflow when it is not in your mouth. What this translates to is that it is harder to breath.
The integrated octo/inflator is basically long enough for you to breath off of, and not a buddy. What this will translate to is that in the case of an OOA situation for a buddy, you would have to hand off your primary and breath off the harder breathing octo/inflator. In a situation like that I would prefer to be able to breath as easily as I can.
I too had considered the integrated octo/inflator, but decided against it after taking ease of breathing into consideration. On my singles setup I have my octo detuned so that it doesn't freeflow, but I have it on a longer hose than my primary, that way I can keep my easy breathing primary and hand off the octo. On my doubles setup, I have identical regs that I can adjust on the fly. I use Apeks regs for both setups. I use the XTX40 for the singles, and XTX50 for doubles.
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