AKL is more unique
WL is more "Disney"
AKL has a new incredible water-play are for kids
WL is a walkway/bus ride/boat ride away from Fort Wilderness and all their amenities including nighttime movies, campfires, pony rides, etc.
AKL has one extra sit down restaurant, but it's also a higher-capacity resort, which results in their food court tending to be more slammed than WL's despite Roaring Forks being tinier.
Both resorts have sit down restaurants open for lunch, but WL's would be more "accessible" for finicky eaters.
And last thing about food, AKL has my favorite buffet (Boma). WL has one of my favorite higher-end restaurants (Artist Point) and Whispering Canyon is one of the "funner" restaurants on property.
AKL has the savannah, and a dedicated bus line.
WL has boat rides to the MK and boat rentals.
AKL has the better gym
Are you planning on working out on vacation?
Right, don't know why I brought that up.
I've stayed in both, and it's a "your mileage may vary" kind of sentiment, but when we used Disney transportation, AKL's line seemed to be more reliable. If you're really planning on doing mostly parks from sun up to sun down (and if you don't have your own car), I'd think reliable transportation would be the only criterion worth a hoot. In this, I'd give AKL a slight edge.