Nope, not a buffet. The food is served family-style. Platters are brought to your table of each item and you can get more of what you like. Personally, with 3 small kids, I avoid buffet character meals. I hate trying to coordinate getting food with catching the characters and trying to photograph the interaction. Way too hectic for me, especially for the $$!
The Garden Grill is very quiet, and my kids love looking over the side to see the Land ride.
You'll love it!