I may be in the minority, but I would choose 'Ohana. We stayed at the Poly last year and ate at 'Ohana on our first night and Kona a week later on our last night. The entire week I was wishing we were eating at 'Ohana again.
Although we enjoyed Kona, there was just something special about 'Ohana. (May also have had something to do with the fact that we were seated by the windows and were able to watch Wishes while we ate).
We are staying at the Poly again this September, and I have 'Ohana booked for two nights and didn't book Kona at all.
Oh, and my kids who were 9, 7 1/2 and 3 1/2 at the time did not choose participate in the children's activities. Regardless, they still talk fondly of our meal there.