Of the two, we liked both but Maya Grill was better food, and far better atmosphere. Service was good at both. Olivia's is just generic-Disney-Dining-room, nothing special about the decor. Maya Grill, on the other hand is pretty awesome--"mayan" temple decor, kind of dark (but in a good way) and flickering fake torches all over (well done, but not real flames, lol.) Kind of like you're sitting in a movie set. Strolling guitarist was pretty cool, too.
It will not be easy getting around to either of these resorts...it's just not easy to go from resort to resort using Disney transport. You have to go from your resort to either a park, or the Transportation & Ticket Center, or to Downtown Disney. Then from one of those locations, you have to get a resort bus for your restaurant location. Both places you can wait 20-30 minutes for a bus, and then each bus ride can be 10-20 minutes depending on where you're going. So it can easily take you 75-90 minutes to get from your resort to one of the out-lying resorts for a meal.