IMO, neither are great, but given the 2 choices, I would choose Ohana.
Not sure when Chef Mickeys will be in full buffet/character swing again, but right now the entrees are prime rib (very rare), turkey and salmon. Sides are not really kid friendly, but I did see a family sitting nearby and it looked like they had a plate of chicken nuggets and fries...so maybe there are other options when you have kids with you. We were a party of all "Disney Adults" (10+)