I upgraded on a spare line to iPhone 5, picked up a nano sim (free) from AT&T store and a nano sim to micro sim adaptor from Amazon (few bucks) so that I can use the new phone with my regular number. In case anyone is wondering, AT&T will put transfer any number on a new nano sim, no problem. I can swap sims back and forth between my 5 and 4s, no problem. But my old number, with unlimited data, will not get LTE on the 5. I guess you need an LTE plan for LTE, which makes sense. Not sure if I'll keep the 5. The speed upgrade is nice, the new connector is a huge pain, not having a battery backup case is a problem (could be fixed in a few months I guess). Screen isn't much different and frankly, the phone feels cheaper since it's so light. With both phones on "4g", I unplugged both my 5 and 4s at the same time Sunday morn, the 5 has a slightly stronger battery. Problem is neither will last a full day with my usage.