I can't speak to Chef Mickey's as I haven't been there. However, I've been to 'Ohana breakfast twice, once this past August and once four years ago. First breakfast was with my sons and extended family, second was just my sons and myself. Both breakfasts were really good. We loved the juice and food, we loved not having to get up for a buffet, and the wait staff both trips were just fantastic (getting hot coffee to us right away, quick waffle refills, etc.).
Even better, IMO, was the character interaction. The characters at 'Ohana are wonderful interacting with everyone at the table, adults and kids. They were just spectacular with my sons this past trip. Imagine two boys ages 10 and 12 who wanted to play rock paper scissors with Mickey just as the parade was about to start. Mickey let them know (using hand gestures) that he would be back after the parade...and urged them to join him in the parade. Well, they are 10 and 12, so eventually (reluctantly) made it to the rear of the parade and came back to our table early. But Mickey didn't forget, and as soon as the parade was over, he was back at our table challenging the boys to rock paper scissors. It was just fantastic. The other characters, especially Pluto, were really good too.
As I said, I can't speak for Chef Mickey's. But 'Ohana breakfast has been really good to my family.