We have eaten at Sanaa for breakfast probably 10 times since they started and we have never had to wait for more than two groups ahead of us to order at the cashier. When we have been most people have ordered to-go, so only a handful of tables in the restaurant have ever been full, usually fewer. I really like the breakfast because, to me, the hot items seem fresher and closer to cooked to order than say the CS at The Mara. If you are just doing grab and go items it will be quite quick (I like the banana bread if they still have it) if you are doing the hot items you will need to wait for those to be prepared which in my experience has taken a little longer than going to The Mara, but with much shorter lines to order.
Agree--love Sanaa for breakfast. You can almost always get a table right by the window for good animal viewing, they have press pot coffee, and the entrees are delicious. Hardly ever more than a few tables full. We love it!