We have dined at each over the years. I would prefer Boma over Ohana, but would state I would select another restaurant having dined at each of these in the recent past...seeing if they improved.
There continues to be a lot of hype over Ohana over the last decade despite its decline in polynesian charm, service and food. The menu continues to be mainstream to appeal to the
DDP diners. If you have not dined at Ohana in the past you will be fine here since you have no point of reference. Not all the meat options may be sufficently cooked in enough portions to be distributed to all the dining guest who desire a portion. Nothing like finally being offered Sirloin Steak when you have already been served your 'Ohana bread pudding. This approach can clearly save Disney money.
Beware your waiter/waitress may disapear and leave you table without service, but this happens at other Disney TS restaurants lately too. Also, responding that you have dined at Ohana may get you less service and attention too. We also do not care for the attitude in the food servers who literally drop-toss bowls of food on your table without a word and run away. Nothing like the days past with the lazy suzan on every table and indiviuals smiled, introduced the food and actually acted interested in their job and role their suppose to be performing.
The theming can add a touch of excitement to your experience but ensure you are seated within the main seating area and not next to the lounge along the windows. Overall, Ohana provides a hit and miss experience in food quality, food availability and timely and polite service.
Boma on the other hand is a buffet so this defines food quality, service and availablity. Clearly not food made to order, but neither is Ohana. While I am not a real fan of Boma and would select it over Ohana.