They are so different, it depends on your tastes...
Both have great dining options, and both are beautifully decorated.
The GF is more formal, and in the evenings they have an orchestra playing music in the grand lobby... a great place to relax and have a drink. After dinner, you can walk to the dock and watch the MK Fireworks (or watch the fireworks while dining at Narcoosee's). Then around 9:15 the Electric Water Pageant takes place on Seven Seas Lagoon.
The AKL is less formal, but more exotically decorated. I've never eaten at Jiko's, but Boma is good. You can watch the animals, and even watch them through night vision goggles at night.
If I were choosing (and money wasn't a consideration), I'd probably choose the GF. We just got back and I would love to spend a romantic evening there with just DH and myself.