Tusker House is the one and only character meal that we've actually come to enjoy. I find that most character meals food is the afterthought, but with Tusker House the food is simultaneously creative and well executed, which is often hard to pull off. We honestly don't even care that much about the characters and would/do only go for the food. So yes, I think its "worth" it in my mind. We also don't do lunch on days we eat breakfast at Tusker just to make sure we get our moneys worth.
I can't speak to Rainforest as I have no experience eating there, but it is at the complete opposite side of the park from ROL so if that is something you want to do you may want to consider eating in the park vice right outside the gate