OK, I voted Tusker House (don't like 'Ohana!)
We didn't care for Boma dinner at all...way too sweet on the veggies/sides/meats and way too cinnamon-y on the meat for us (for example, red hot cinnamon flavored ribs...uh, no, not tasty. We love BBQ...we love ribs. Cinnamon red hots is candy, not sauce, lol.) Coupled with the food we didn't like, Boma was a mad-house when we were there. Packed, dozens of unaccompanied kids in the buffet lines...ugh. We go to many character meals, and found Boma (with no characters) was busier, louder and harder to navigate than any of the character meals we've gone to.
Now we loved Boma breakfast. Wonderful food (including some ethnic offerings) Much quieter and more relaxing. And outstanding coffee
We did like Tusker House dinner...the usual Disney buffet items, plus a few slightly more exotic sides & meats. Enough to be interesting but not in-your-face different.
If you're set on trying Boma, be prepared for the transportation issues. As others have said, if you're not staying at AK Lodge, transportation to/from Boma can be a challenge. If you're leaving AK before your dinner, you can just take the AKL bus. But then to get back to your resort is more of a challenge. You'll have to take a bus from AKL to a park that's still open (or DTD) and then catch your resort bus. Or drive yourself if you have a car there

Or take a cab back to your resort if no car.