We ate at all three this past trip.
TH breakfast seemed like very common US breakfast fare: sausage, biscuits and gravy, breakfast potatoes, donuts and pastries, tater tots, coffee cake, waffles,... We had 10:40 reservations, so we also got some of the lunch items. Lunch seemed to include a few more 'exotic' foods (like potato and pea samosas), but still had mostly common (the the US) foods. The buffet was clean and well-stocked, but it didn't have anything that I now crave. (Note that TH is a character meal. We saw Mickey, Donald, Daisy, and Goofy.)
Boma dinner had a small salad bar (lettuce, tomatoes, cheese, dressing), plus a few pre-mixed salads. They also had fruit; soups (oxtail stew, squash soup, chicken curry soup, and a vegetable soup); a 'children's' section with items like mini corndogs; an array of mini desserts; and things like salmon, brocollini, mashed potatoes,... There were some more exotic foods (bobotie), but they weren't in the majority. The food was better than your typical buffet, but I wasn't totally blown away by it. (It was my brother's favorite meal of the trip, though.)
Sanaa had the best atmosphere. We had 5 pm dinner, and were seated (without having to ask) by a window. During dinner, we were able to watch zebras, giraffes, etc. There is also a deck with some rocking chairs you can go out onto to watch animals before and/or after your meal. A couple CMs were out on the deck available to answer questions, too.
The bread service at Sanaa was really good - I would highly recommend it. My brother and I each had then potjie inspired dishes: I had butter chicken and lentil dhal, and my brother had two different seafood dishes. The portions weren't huge, but were filling. (The potjie cost $23.99 I think, and my brother noted that he'd have paid that much or more for the same amount of seafood curry at home.) DH isn't much into curried dishes, so he got the fish and seemed to enjoy it. DD had grilled chicken breast with basmati rice and vegetables (they had typical kid-centric meals; DS shared with us).
Of the three, I liked the food at Sanaa the most. (I tend to prefer restaurants where you order off a menu over buffets.) Each had plenty of foods for less-adventurous palates. I would choose Sanaa to dine at again, especially for the bread service and animal watching.
