I would love to do O'hana for dinner. Sadly I have never been able to score a ressie. We are AP holders and we always plan our trips within a month of going so it has just never worked out. *tear*
We did dinner there last year and it was very good. The waitress we had was the best I have ever had anywhere. We had late reservations and the kids were exhausted so she kept the courses coming like clockwork so we could eat, enjoy and leave. Everything was amazing from the appetizers to the dessert. This year we are going there for breakfast--I just have to try the Tonga Toast that everyone raves about. I don't think you can go wrong either way.
We've never had breakfast there, but we did have dinner during our very first trip to WDW about two weeks ago. It was WONDERFUL!!! My favorite of all the TS restaurants that we tried! I would love to go there again!
Having had both, I prefer dinner. I think that the sushi bar's offerings are one of the restaurant's greatest assets. Between the sushi, the Hawaiian bread and their interesting appetizer selections, you can have an outstanding meal without even glancing at an entrée.