I've used one for a long time, well, actually the Tusa version of the same thing (made in the same factory... just has blue buttons) and with my setup, it is not hard to use and still look at the OOA diver. Really, I kinda' like it, since if someone is to rip a reg out of your mouth, and I've heard numerous reports of that, even when a conventional octo was present, it would be faster and easier for me to find the Air 2 than an octo on my side.
But in another sense, I think it's just a personal preference, and doesn't much matter to me. I have thousands of dives, and never once had an out of air emergency. But I always make sure I know how much air everyone around me has... maybe that's why.