If you are visiting IOA you MUST eat at Mythos.
Mythos Restaurant®
Food: Overlooking the inland sea, Mythos features fresh, contemporary cuisine, a full bar including wine selection, as well as family favorites like fresh salads, pizzas, and burgers.
Type: Casual, Full Service
Reservations: Accepted. Call Islands of Adventure Reservations at (407)224-4012
Serving: Lunch and Dinner daily
If you are only visiting Universal, I like Finnegan's a lot.
Finnegan's Bar and Grill
Food: American/ Irish: Fish 'n Chips, Corned Beef and Cabbage, Guinness Beef Stew, Sandwiches, Salads. Full bar with Happy Hour Daily
Type: Casual Full Service
Reservations: Accepted. Call Universal Studios Reservations at 407-224-3613
Serving: Lunch and Dinner daily