You guys need to remember your so call factory unlock that you pay for can get shut down and you end up being the looser. When AT&T finds out those phone not on there system
Um apple has sold unlocked iPhone 5's in the US since its release date, just ask for AT&T no contract purchased at full price and activate out of the box with a non AT&T SIM card, I got my iPhone 5 on September 22nd and have been using with Tmobile USA since (and same with a few of my other friends as well). All apple did was admit the y sell unlocked 5's now, but they have been since the day of its release. Also you can factory unlock any AT&T iPhone for $4.50 via eBay as well (just sayin)
but I still use ATT. I see no point missing out on 4G and LTE by using iPhone 5 on TmobileUSA, which limits you to EDGE speeds, not even 3G afaik
I just unlocked to prove it was possible.