I had the GF pizza with Udi's crust topped with sausage, and had a reaction because the sausage isn't gluten free, but the server told me that when I ordered. Since I only have an intolerance, I didn't think I'd have a reaction. The second time, I ordered it with tomatoes, and it was great! The only change I'd make is to ask them to make sure they cook it long enough so it's crispy and the toppings are melted.
Pizza Hut offers a gluten free pizza using GF Udis crust. The staff was super knowledgeable about how it was prepared. My husband could see them using dedicated pans, kitchen utensils, etc. The boxing process takes place in its own dedicated area as well. Delicious tasting and safe!!