Yes, you have to pay for DQ to eat at Cheesecake.
So I will respond assuming you are planning on having some fun in Disney Quest.
We have been twice and both times ate at Cheesecake, even though we could leave to eat and come back.
The food is very good and we think one of the best values there.
We are a family of 5 including 2 teenage boys. We ordered a large pizza with everything, a few orders of fries, and an order of garlic rolls (my passion). We could not finish it and it was VERY reasonable. Wish we had seen the cups with discount refills before we ate, oh well, next time.
The best was we didn't waste alot of time in DTD when we could be playing. Plenty of spots to eat, including a large room that looks like you are on a cruise ship, that is used for private parties, but open if not. It is a quiet place to eat.