Turkish visas are single-entry, so as expatinglasgow notes, you'd need an additional one to leave the airport to get some food. However, the price of the visa is only 20 bucks these days, which is not all that daunting if you really have time for a good lunch. There are nice waterside restaurants not far from the airport, so you don't have to go all the way into town.

I flew TK in C from JFK-IST about six years ago and it was OK, but nothing special. No flat bed seats, which for me at this point is a deal breaker.

P.S. Just noticed that you posted this in the Middle East forum. Be aware that Turks are quite sensitive about having their country (mis)classified as the Middle East. They are quite adamant that it is not.