There are a few hidden gems at the Studios. You just have to find them. As for where to eat, the the Flatbed Grill has an excellent Chicken Caesar wrap, and very good BBQ sandwiches. The Backlot Express has a very good Turkey Sandwich, and the grilled veggie sandwich is also very good. Both restaurants also have the usual kids stuff: burgers, hotdogs, fries, etc. But we like them because you can get different things to eat, like the Caesar Wrap.
The best "hidden gem" that we've found for food at MGM is the "Lounge" next to the 50's Prime Time Cafe. Most people think of it as just a waiting area for the 50's Prime Time. But, it is actually a bar where anyone can enter, and you can order food, too. We've had great food there, and cold drinks, too. The 'smores can't be beat! And you don't have to have reservations for the restaurant to go in there.