Two of the best EP restaurants IMHO - tough decision!
For me, it would depend on whether or not we have another character meal planned. If seeing Mickey & the gang elsewhere, I would skip GG. But it is one of our favorite character meals (along with Donald's Breakfast & Cape May Cafe).
Tutto Italia is probably my favorite of all Disney restaurants & a must-do for us every trip. So if I had to skip it, it would have to be for something really good!