Both Character Meals are really great but for different reasons. If I had to choose, I'd select Tusker because of a combination of better food selection, loved the gang in their safari outfits and being inside a park was a bonus so we could jump on the Safari. If you have time, do both! They're great for different reasons.
Both only serve the regular Nescafe coffee unfortunately. Very disappointing given the wonderful food available, I would have expected Disney to offer much better coffee! Most days every morning, we did a Starbucks run before going into the parks.
Ohana
Character interaction was wonderful. There is Stitch, Lilo, Mickey and Pluto. We were there on a quite day (There was morning EMH at Magic Kingdom that day) but we actually got the characters over to our table twice because hardly anyone was there and they were literally just standing around. We took alot of photos and video during the breakfast and they gave us alot of time. They also do a dance around the room every half an hour that you can join in with.
Food was quite good, much smaller selection then at Tusker. The food is brought to you on skillet and we could ask for extra as well. The food cooled down fairly quickly though we noticed.
Service was quicker then at Tusker. Bill was settled within 5 minutes, we requested more food and coffee and it was there very quickly.
Tusker House
There is a much large food selection available here. It is a buffet style meal and there is literally anything you could be hoping for. Hot food, breads, fruits, cereal. I have allergies and the chef offered to make me anything I wanted in particular.
Character interaction was terrific. Loved the gang in their Safari outfits! They did a conga through the restaurant as well, which was fun. We weren't rushed and could take as many photos as we wanted. It was quite busy and we had the earliest ADR you can book.
Only downside was being a buffet, you need to leave your table to get the food. The servers are very good but you need to keep an eye on when the characters are coming around so you don't miss anyone. We found our server quite slow when we asked for the bill and that took about 10-15 minutes to finalise so we had to wait around for awhile.