no issues for me
3 snow storms this year thus far, VERY rare for where I am, and one day at just 7 F, while we spent an hour and a half outside building snow men and playing with our child, iPhone exposed to the elements most of that time since both of our digital cameras refused to work after about 10-15 minutes at that temp.
I found, even at near 10 degrees F, I could not keep the iPhone in my hand more than 5 minutes or so without handing it off the the wife and putting my gloves back on. For several periods of about 10 minutes each, we set it on the porch and continued to play. At no time did I see anything more than a sluggish LCD, and that was only after an extended period of no activity. The phone recoded video, made calls, and uploaded to the net without issue. I can't imagine using it outside in any lower temps for more than a few minutes, especially in contact with one's face to make calls. My bluetooth headset failed quick in those temps.
Super cold, below zero F, I don't imaging anyone's phone is likely to work in those temps for very long unless it has some form of heated casing. If they're making Apple refund phones, they better be making everyone else do so as well, unless the phones are in fact rated to below those temps (which LCD itself can't be, so it would have to be some odd display tech special made for artic temps).