The food was very good and the GF menu was very specific about what you could and could not safely eat. There were a lot of options too, as far as what to eat. My biggest concerns were that in a production-line style restaurant(much like moes or chipotle) many people handled my food and I had no way of knowing what each worker had touched.
They don't have a GF menu and while they may use fresh ingredients the server informed me that they do throw flour on then grill while cooking. Since they use the same grill for everything there's no way I was risking it and didn't eat.
Peppers is a great option for great GF food! I just avoid the obvious gluten foods and have not had any issues. Their dishes are made with real ingredients which makes it very easy to find good options. They also have great margaritas :)