Not a huge fan of either one. Since your are considering LTT I am assuming you plan to be in the MK that day. So the first consideration I would be making is do I want to take the time to travel out of the park in relation to your plans and park hours on that day.
If leaving the park is no big deal, then I would be chosing Ohana. It has something of an atmosphere, we sat by cooking area which was nice but I would have loved being by window as well. I think next time I would ask to sit away from the "childrens' games" just because my kids are older and we would prefer that. Food was good, just was alittle hard to get more of the meats without flagging server down. I am not a huge carnivore, and that truly is the focus of the meal here, but my guys loved it.
I always avoided LTT just because of the mindset I had with "stouffers" macaroni. I don't pay that much for frozen mac & cheese. But we tried it. The mac & cheese was not edible. The meal was basic T-Day fare, the tables so close together we were constantly being bumped and we could hear everyone's conversations. For the price, no I won't go back. And as far as decor, I think the upstairs at the Columbia Harbour House (counter service) is decorated much nicer in the Colonial mode.