I thought Boma had the better food. The atmosphere you can't compare: one has characters, the other has not. I think Boma is slightly lighter, something I prefer for breakfast, but both are similar in decor I would say.
I really enjoyed both and I think you can't wrong with any of them.
However, one thing we did and which I enjoyed a lot was: getting the lastest breakfast ADR possible at Tusker House. For us this was 10:20 am. We got to AK for rope drop (just had a snack in the room to keep us going), went on EE, Dinosaur, Primeval Whirl and got a FP for the Safari before breakfast which was then good for a ride on the Safari immediately after breakfast.
When they started to wind down with breakfast, the buffet still had plenty of offerings, everything was still available when we left, and since the restaurant was already half empty and we had loads of character attention. Daisy and Mickey even visited us three or four times!