We just came back from both and charged both meals to our room. We ate at T Rex twice, and the first time the waitress said it would take longer to do our bill since we were putting it on our room charge. Two days later the waiter we had said nothing and it was done quickly.
We have TIW, which we used at both places, but if I remember correctly both places asked us if we had the
DIsney Dining Plan, maybe they want to tell people that they don't accept it, that I'm not sure about.
We loved the food at T Rex, we ate there twice with four people and we all had something different both times and everything was good.
Only one thing was they offered a margarita with cotton candy on it. The waitress that we had was not too good and she brought out the drink for me and the cotton candy was in the glass and before I could say anything she took the drink which was in another glass and poured it on the cotton candy and then it disappeared. I wanted to do it myself so I could take a picture.

Oh well maybe for next trip. The picture shows the cotton candy on top of the drink.