Just went thru that today, got 2 Black iPhone 5's both 16 gb no matter what we did, AT&T replaced nano sim, and Apple looked at it, one phone would not connect to LTE. Apple is booked at my store until Wednesday and would not give me a replacement even though a tech guy confirmed the phone is bad, so they said either return it, which we did, or wait until Wednesday to see about a replacement with a genius, or they tell you to call them everyday to see if they got more new ones in stock.
That being said with all the driving we have done to get to our store, we decided to take my 5 and give it to my wife who was coming off a IP4, and I told Apple keep their phone and I will stick with the IP4S until I decide what I want to do, either wait for a Black 32 GB, or go to a Samsung Note II, either way my 4S works perfect and I am fine with it, just not sure Apple handled it well, I think they do such a bad job on these releases, and they covet everything so well, they do not care about customer satisfaction.
From now on if I stay with the iPhone, I will never get one on release day, I will wait until they have stock to get what I want per color and size, this way all this stuff doesn't happen again, as this did with the IP4 release.