IME it’s fine - seems to be basically the same offering as the JFK dining but far nicer room and moderately better executed. They have wine-in-a-bag machines which have caused predictable outrage on here but it’s all perfectly drinkable.

For me it’s entirely moot whether it’s better than the food on board. I’m rarely flying to/from IAD for leisure so if I want to maximise my sleep on board then an edible meal in the lounge is ten times better than any meal on board, however delicious that may be!