For 1BRs the decision is easier, we prefer Kidani (larger rooms, separate shower stall, etc.) For studios, I would lean towards Jambo House for the following reasons.
The Jambo House studios have a better bathroom layout. The vanity is in an open area, the toilet and shower are in a small room to the side. That leaves the vanity available for use even when someone is taking a shower. In Kidani, the entire bathroom is in an enclosed room with the toilet in a smaller room within that space. If someone wants to shower in privacy, the vanity is not accessible.
There are three restaurants in Jambo House, two of which offer a hot breakfast, The Mara for quick service and Boma if you want a breakfast buffet. Kidani has Sanaa which is a great place for dinner but it doesn't offer breakfast. We don't mind the walk from Kidani to Jambo and back at breakfast but if you are trying to get up and out quickly in the morning, it would be handy to have The Mara right there.
If booking a Savanna View room I prefer to be on the lowest possible floor. Kidani offers that possibility though you could still end up on a high floor despite requesting a lower one. All of the
DVC rooms in Jambo House are on the 5th and 6th (Club Level) floors so the tree tops will be blocking part of your view.
The studios are comparable in size so that isn't a factor.