They are two totally different dining experiences, but both are phenomenal. Sanaa has some great Indian food and during the day has some good views of the animals. Jiko on the other hand has the largest selection of South African wines outside of South Africa (at least I think that's the claim) and is much more a fancy dinner inspired by African flavors. If you both don't mind getting dressed up a bit, Jiko is a great choice and would probably take the edge for a special meal, but both are great.