For room, the 1BR at Kidani beats the 1BR at Jambo by a large margin. Kidani 1BR is nicer internally, 100 sq ft larger, two bathrooms, master bath has separate shower and tub, and has more closet space. Jambo bathroom has combined shower and tub and step over into tub is very high, and you need to cross a small hallway between the master bedroom and bathroom to get to bathroom which hallway can be seen from living room.
As to resort amenities, Jambo wins in having three restaurants (table service, buffet and counter service), to Kidani's one (table service that is not open for breakfast), the much larger lobby and store, and larger pool with lots of shade areas to find at the pool area. Kidani does have the much longer slide and the elaborate kids water play area. If you have a car, Kidani has ideal under building parking and, with elevators along the two wings, you can always find a parking space fairly close to your room. Jambo parking is in a huge lot across the street from the front entrance and walk from car to room can be very long. With savanna view at Kidani you can get lower floor view for more direct site line to animals while at Jambo all
DVC rooms are on the fifth and sixth floor. Kidani has one very large (Sunset) and one small (Pembe) savanna and Pembe has no giraffes, Jambo has three savannas (Sunset, to west, Arusha in middle, and Uzima to the east), and Arusha is perhaps the best of all the savannas. Park buses stop at Kidani first, Downtown Disney at Jambo first, with the result that you have some risk at Jambo during rush times in the morning of finding standing room only on buses to the parks.
We base the building decision on room. If studio, Jambo is the one because studios are about the same size at both and Jambo has the better amenities, If 1BR or 2BR, we do Kidani because the rooms are so much better.