If the comfort and size of the room is an important issue with a 1BR then Kidani wins by a large margin. The Kidani 1BR is about 100 sq ft larger than Jambo's (a very noticeable difference), has two bathrooms to Jambo's one, has a larger master bath with a separate tub and shower compared to Jambo's combined tub and shower where the tub has a very high stepover which can be a real entry issue for any older person with any knee issues, and Kidani has more closet space.
Jambo has the larger lobby and much larger store. It has three good restaurants: Jiko, an expensive but very good table service, Boma, one of the best buffets on site, and Mara, a counter service with lots of seating including some outside in the shade. Kidani has only one restaurant, Sanaa, a very good table service. Jambo's pool is also larger and has far more places to find shade, but Kidani has the much longer slide and a kid's water play area (for anyone 2 to about 12) that can't be beat. It also has more tables and seats under the roof in the bar area than Jambo has. If you have a car, Jambo's lot is across the street from its front entrance, meaning a likely long walk to your room while Kidani has under-building parking almost throughout the building and with three elevators along each of the two wings, you can usually get a parking space close to your room.
A major difference is building length and walk from lobby or bus station to room. Jambo's two wings are very long and provide quite a walk from an end room to amenities (you may see posts by members emphasizing how excruciatingly long the walks can be at BWV from room to lobby, and Jambo's are longer). However, Jambo has nothing on Kidani which has the longest walk down an internal hallway from end room to lobby or bus station than any hotel in the world (that means on earth not just WDW). The walk from the end of its south wing (closest to Jambo) to the end of its north wing is more than 2/3 mile and from bus station to end room on the north wing is well over 1/3 mile (typically five to six minutes normal adult pace, or eight to nine minutes with little ones in tow -- distance is about the same as it is from the base of World Showcase at Epcot to Germany).
All rooms at Jambo are on the fifth floor (except for club level rooms on the sixth floor that are over the lobby, the only place there is a sixth floor). Jambo has rooms that can overlook any one of three savannas, Uzima (to the right of the buidling), Arusha (in the center), and Sunset (to the right and the largest of all savannas). All three are fine with Arusha being considered by many the best and Sunset a close second. If you have savanna view, you may want to ask for Arusha savanna view there and along Zebra Trail (the right side of the building) which not only has good views but room looks west and thus does not get blinding sun coming in during the morning. Avoid requesting close to lobby or to transportation because savanna view rooms in that area do not have the best views. If you have standard view, be aware that more than half the standard view rooms actually have savanna a view (the rest pool view), with decent views but just not quite as good as savanna view rooms. If you want to try for savanna view there in a standard, request a room along Kudo trail (the left side of the building where the exisiting standard views all have savanna view).
Kidani overlooks two savannas, Sunset to the east of the buidling (over which are more than 80% of all savanna view rooms at Kidani), and Pembe (on the north to northwest side of the building; the front entrance faces west), which many consider not that good including because it has no giraffes or zebras. If you have savanna view, one request made by many is Sunset savanna view (with a high chance of getting it simply because that request includes most savanna view rooms). A second request made by many is for a room close to lobby to avoid the long walks. Avoid that request with savanna view because it is one now having a significant risk of not being met because so many make the request, and if they cannot meet a location request, they just put you in any available room which most often is one near the end of the hallways, far from the lobby. If you want to be close to the pool (on the north wing) and within striking distance of the lobby and bus station, request a room near the Rafiki elevator (down that elevator to ground/parking lot floor provides shortest possible walk from the building to a gate that enters the pool area). If instead, you want to be close to the bus station, and faily close to the lobby and within striking distance of the pool, request a room near the Timon elevator (on the south wing). Down that elevator to second floor provides a very short walk to a door that leads directly to the bus station. If you do not mind long walks and want the shortest possible walk to Jambo, request close to the Zazu elevator (from the ground floor of that elevator, you have about 1/4 mile walk to Jambo's front door. Another request some like to make is lower floor to give a more direct view of the animals but higher floor gives a good panoramic view and personally either is fine to me.
If you have standard view, most such rooms are not hugely far from the lobby and overlook either the bus station and some parking lots on the south wing or hills and the pool area on the north wing. For view of pool, request room near the Rafiki elevator and high floor. To be near bus station request near the Timon elevator and also request high floor (so you may actually see a little over the bus station). There are some standard rooms at Kidani that actually have savanna view of the Pembe savanna. If you want to try for one of those with standard view request room near the Pumba elevator. Be aware, however, that getting one of those rooms means you will have very long walks to the lobby and bus station.
If you are in Kidani and want to get to Jambo, you have three options: (a) walk: front entrance to front entrance is about half mile but distance can be up to about 5/6 mile from an end room on the north wing to a 1/4 mile from the Zazu elevator on the south wing; (b) take the shuttle (a mini-van) which runs constantly day and evening between Kidani's front entrance and Jambo's (longest wait is typically no more than 15 minutes); or (c) get a park bus that starts at Kidani (the usual start place) and stops at Jambo; returning from Jambo would be the Disney Springs bus; note you have to be careful there and ask the driver because very often the MK bus, and on more rarer occassion even some others, may run directly from Kidani to the park.