Well if my story not true, than Apple is in a big trouble now, because its means there are many Iphone 5s's are faulty and its more likely a hardware issue. My "first" I5s what I purchased from O2 on the 29th of September and updated to 7.0.2 the same day, had 3G issues in areas where my I4 was working fine before, and had a strange headphone jack problem(thats why Apple gave me a new one).
When I updated to 7002, all my apps were crashing, or had audio problems in skype, mobil voip or even voice recorder. It restarted itself like a crapy android phone, it was a nightmare.
Since I got the replacement, I left it as it comes(on 7.0), and I use it for 9 days now, it did not have any problem yet. I am extremly lucky, or ios7.0 works better than 7.0.2.🙂