If you get there very early I would say no. We ate there twice and both times it was early. We had an ADR once but not the second time, we just walked up and the place was almost empty. I don't know about a more busy time. I would say if you definitely wanted to eat there, make the ADR. If it doesn't matter I would just wing it.
We always make ADR's for breakfast there. I do usually travel at busy times like spring break, summer vacations, president's week, basically anytime the kids are out on break. I've always found there to be a crowd waiting to be seated there.