I would choose Sanaa over Boma. Here is why: at Boma, as a mom of two girls, I hardly ever sat down. I was up getting food for them, then taking them to the bathroom, then getting more food then getting dessert. It was crowded and there were lines so it was hard for me to enjoy. The food is wonderful, but it is also expensive. My daughter and I ate lunch at Sanaa for less than one adult buffet at Boma.
If you can do both, I would do Boma for breakfast and Sanaa for dinner or lunch.
I found that being served was easier than a buffet with children, even though there is more variety at Boma. Sanaa has some good choices for picky kids, and their desserts for kids are beautifully presented and tasty. One of the best values on Disney property, IMO.
Don't get me wrong. I would go back to Boma. It is great. But we prefer Sanaa for atmosphere and value.