We stayed in the Jambo grand villa and loved it! The kids in our group thought having a pool table in the room was the coolest ever. It is a beautiful villa.
I don't think you could go wrong with either one. I personally never saw the Kidani grand villa, so I can't comment on it.
Jambo is in my view rthe best GV on site, single story giving large living and dining area, large balconies, pool table in its own room, huge master bath with centrally located tub from which you can view a large in-wall TV.
I have only stayed in the Jambo House GV so I can't actually compare, but it was absolutely the most beautiful hotel room I have ever stayed in. The pool table was an added bonus, as we were traveling with 6 adults, four of them in their 20's. I would highly recommend giving it a try!
We have only stayed in a GV in Kidani, but it was absolutely incredible. If you have people who would be interested in the pool table I would go with Jambo.