I just did this, round trip to the U.S. and back; however, my layover was 2 hours one way, and three hours the other. It is safe at the airport – it’s not in downtown Istanbul. There is a hotel that you can enter directly from the airport. I took a baseball cap to wear while I was there, and I ended up not even using it. There were so many different kinds of people there, nobody was paying any attention to me. The shopping area is very nice. I will say that I was very impressed with Turkish Air – all personnel were quite friendly and efficient.