Being a noob, my main safety complaint is the blindspot a few other folks mentioned. Being able to see your buddy periodically is good. Having to roll around to see where they are is annoying. On the second dive, it doesn't seem to annoy me much because I'm more relaxed, my trim is better, and tend to be more aware of my surroundings.
Actually this is a gear safety complaint that plenty of people disagree with. Not trying to start a flame war, but I'm gonna put on my asbestos underpants just in case. This is my own observation, made on a checkout dive, so this may be stupid. My wife and I used rental gear during our checkout dives and we had to do an air share ascent drill. Her rig had an Air2 on it, and while we did the drill successfully, practice was the only way it was reasonably possible (used the same gear in the pool too). The controls were fine and it breathed ok, but maintaining eye-contact during the ascent was very difficult (unless you work for Cirque du Soleil, which we do not). My rental gear (from the same shop) had the usual octo and was much easier. I'm glad we did the drill with an Air2 because I'll end up diving with somebody with one someday. I'd just hate to have one and have a buddy who has never done an air share with it though. This being said I'm going to give the long hose (and some practice quarry dives with it) a shot. Looks to be much safer. (Not drinking the Kool-Aid though...)