I know that some of you eat greek yogurt, and it seems to be a good snack food, but is it okay to eat the greek gyro sauce and the grilled chicken?

Technically speaking, you can eat whatever you want. Anything is ok within moderation.

With that said, I'd try to find out what's in it. Some is very fatty, so in which case I'd want to use very little. However, if it was leaner and not so fatty, I'd indulge in a little more.

I don't know if you have a costco by you but they have (in the refrigerated section) a tub of the tzatski (spelling, sorry) sauce that is lowfat/low cal (theirs is made with Greek yogurt) and very yummy. I use it in moderation and my kids like it for veggie dip.

No Costco in my town it was actually a Greek restaurant work ladies were going to, and I wanted to try to find an acceptable lunch to be able to go with them, I went ahead and got the chicken gyro with no pita and no sauce and got a house dressing instead. (which was mostly vinegar, oil, and spices)

I would ask if they make the sauce (if not ask if they will tell you the calories listed on the container). If they do make it ask whether it's made with low fat yogurt. Full fat Greek Yogurt has has much fat calories as ice cream. Trader Joe's was giving samples of their full fat French vanilla Greek yogurt. I said to myself this tastes like melted ice cream. Well when I read the container it had the same calories!

Also often the meat in the Gyros are a mixture of ground up meats. May not really be that healthy. Most Greek places will have chicken Kabobs, I would probably say that would be a MUCH better option.