Mount Vernon has a nice, well-researched museum.
However, it isn't about George Washington at all. It is entirely devoted to the slaves who lived on his plantation.
I was there a few years ago and they did pay a lot of attention to the lives of the slaves, but a lot of attention was still given to George & Martha. Maybe that has changed since then.
Fortunately it is private, not public. But I hope they can protect it if a mob descends on the place.