AKL is the easiest. It's a bigger resort.
I'm sure it really depends on the time of year as well. When I tried to get WL for the trip the first weekend in December, it was booked except for the Presidential suite. A lot of people like to stay there for the holidays. I, like many others, think it is the best resort around Christmas time. A lot more demand then. At other times of the year, it may be just as easy to get as AKL (but keep in mind the discrepancy in number of rooms at the resort).