We had dinner at both Kona (8/5/08) and the Wave (8/12/08) recently.
Food was better at the Wave. All of us preferred our meals. I had the fish, DH had pork, oldest DS had pasta with shrimp, and the "kids" had pizza and pasta. Desserts there are also wonderful.
Kona's food was good, but my mahi mahi was somewhat dry. DS liked his shrimp and scallops. Kid meals were typical Disney kid meals (at the Wave the food for kids was not the same stuff you've seen everywhere). Dessert was good, but not super memorable.
Service was mediocre at both. At Kona, our server was pleasant but not that helpful and did not appear as frequently as I would have liked.
At the Wave, the server was pleasant, but she really irritated me for two different reasons. First, she took my KTW card and kept it during the meal. Whereas a few other servers asked to look at it so see which dining plan we were on and such, this one kept it. When I asked her about that, she said she would give it back to me after the meal. She also was the only server on this trip who asked me how I would pay the gratuity. And, when DH and DS just asked for ice water, she said, "I'll bring you some bottled water to go" and then promptly did that. This Evian water added $13.00 to the total which of course was her attempt to increase her tip.
I haven't eaten at GFC, so I can't help you there!