We have stayed at both and quite frankly we love both! Some of our pros/cons are:
Kidani - pros:
More laid back and quieter
Parking right near your room (big plus on longer trips!)
Buses do stop here first (except Downtown Disney bus)
Fantastic pool, slide and kids water area (adults can have fun here too

)
Kidani - cons:
Room can be FAR away from pool
No concierge rooms (if that is important to you)
very small hot tub
Jambo - pros:
The food and drinks - Boma, Jiko, Mara and Victoria Falls bar!
Fantastic hot tub
Concierge rooms!!!
Jambo - cons
Can be VERY noisy
Second on bus service (often have to stand depending on time of year)
Parking can be problematic
Either way you will have a great time. Kidani is our deeded home but all of Animal Kingdom feels like home to us!