We've stayed at both, and both are beautiful. There are good dining options at both, but the pool is a little nicer at the AKL (they have a zero entry pool). We didn't get Savannah view at the AKL, so the animals were only a minor part of our stay there. At the WL, we rented bikes and rode over to Fort Wilderness and the stables to see the horses.
If I had to pick one, I'd go for the WL, mainly because of its proximity to the MK. Getting to and from the MK from the AKL was very painful. We found we had long bus waits at the MK when going back to the hotel. The WL has a boat, which is fun for kids, even if it does take a little while.
Either way, you can't go too wrong.