If staying in a studio or Grand Villa, Jambo is our choice. The studios are about the same size as the ones at Kidani and the shower is in the little room separate from the vanity area; at Kidani the shower is right there in view of the vanity area. The grand villas are single story with huge balconies, a pool table room and a master bath with a large TV to watch from the centrally located tub in the master bath. Kidani's are also very nice two-stories but we feel the Jambo GVs are the best on site. Jambo has the much larger lobby and store, a true bar area for just getting drinks, and a very good table service (Jiko) and buffet (Boma) restaurant and a counter service restaurant (Mara) with lots of room and tables. Jambo also has the much larger pool and there are a lot of places to find shade.
If staying in a 1BR or 2BR, Kidani wins. They are about 100 sq ft larger than the ones at Jambo, have an extra bathroom, more closet space, and are just overall somewhat nicer internally. Also you can get dedicated 2BRs (can only be used as a 2BR) and not just lock-off 2BRs (connecting 1BRs and studios) which is all of the Jambo 2BRs. The dedicated gives you one long balcony that runs the length of the two bedrooms and the living room while the lock-off has a wall dividing the balcony between the studio and 1BR. The dedicated 2BR also has two queens in the second bedroom rather than the queen and pull-out sofa double that are in the studio portions of the lock-offs. Kidani also has ideal under-building parking and with elevators along the wings you can park fairly close to your room no matter where your room is. Jambo has a big lot across the street from the front entrance to the building. Kidani's pool, though smaller, has the much longer slide, and the elaborate water play area for kids (with things for tweens and below), but shade is diificult to find anywhere near the pool since trees are still growing. Kidani has only a table service restaurant, Sanaa, which has no breakfast service, but it is one of the best restaurants at WDW.
Kidani, which is all
DVC, offers both low flooor and high floor views, and many prefer a lower floor which gives a more direct sight line view of the animals. (Note, the rooms are on floors 2 to 5; the lobby is on 2 and the first foor is the under-building parking garage). All DVC rooms at Jambo are fifth floor and club level on the sixth above the lobby (the only place there is a sixth floor at AKL).
For savanna view, we prefer at Jambo the Arusha savanna (one in the middle of the building), along Zebra Trail (the right side of the u-shaped building) which gives good views of animals and faces west to avoid sun in the morning. At Kidani, we prefer the Sunset savanna view (rooms can view it to the east, north or south, depending on location) which is the largest savanna at AKL and one side of Jambo also faces it. About 80% of the Kidani savanna view rooms face Sunset. Pembe is a smaller savanna on the northwest to north side of Kidani with which we are not impressed including because it has no giraffes (instead a much smaller giraffe cousin called an okapi). Also be aware that the Kidani building is very long; the pictures you see on-line do not accurately portray the distance but it is about 1/3 mile from the lobby to the end rooms on Kidani's north wing and only a little less than that on the south wing (the front entrance to the building faces west). As a result, at Kidani we usually request close to lobby or close to community hall (those are similar requests and include savanna view rooms that face only Sunset savanna). Note that close to lobby is not the best request at Jambo as rooms away from the lobby provide better savanna views.