Ok, here is my experience with the Airave and my iPhone 5 and an iPhone 4S. The 4S, absolutely no problem connecting. It was perfect. Strangely enough, the Airave we connected to one day tinting the windows on a semi-truck, wasn't ours. My iPhone 5 however, wouldn't connect to EVDO, but maintained a very decent 1x voice signal. At least I had that. Didn't see any worse battery drain issues on it other than the phone calls that last 20 minutes to half an hour.
Edit: Does anyone have the ability to share their airave that I can put on my account so when I'm at home in Pahrump, I can attach my iPhone's to it. My iPhone 5 is having connection issues with the local site, and my friend is being told by people that she sounds like she's underwater.