Both resorts are perceived to be an increased away from the parks, but the truth is, transport to the parks is probably faster from Animal Kingdom, Kidani Village, because the buses only make two stops - One stop and Kidani and then one stop at Jambo House, before heading out to the parks. Unlike Old Key West where there are a half dozen stops as the bus winds its way through the resort. And each stop can add 2 to 3 minutes to your trip, if things go as bad as they possibly can. Also, Disney is aware of the concerns people have for distances, from AKL, because it is 'clear out there away from everything else, except Animal Kingdom Park.' So they seem to try harder, and the buses seem to run more often and more regularly.
The decor and ambience at Kidani wins hands down. Kidani has the largest collection of African Folk Art outside of Africa.
Kidani has access to much better pools and restaurants (Uzima pool at Jambo is one of the best at Disney World. The Kidani pool is a favorite of families with younger children. Boma, Jiko and Sanaa are some of the best restaurants in Disney World - if African-Indian-American fusion food is acceptable to you). It does not have a quick service restaurant for breakfast, but you don't need to go next door to the quick service at Jambo House, because the Sanaa restaurant at Kidani functions as a quick service breakfast restaurant in the mornings, and a fine dining, wonderful restaurant at night.
The staff at Animal Kingdom Lodges is usually noted for being super nice.
Animal Kingdom is unique in the United States, and probably the whole world, outside of Africa. There are no other hotels ANYWHERE where they build the hotels around a 'natural' landscape, complete with African wildlife.
Old Key West has a relaxed atmosphere, since it is separate buildings, spread out throughout the resort.
Old Key West is fairly close to Disney Springs. Just walk down to the water and catch a water taxi to Disney Springs.
Both resorts are good, and both are different. Just decide what amenities you like, and enjoy the trip.