Just got back today from being there Thursday. 750ish miles each way.
Worth the trip, although it's not a picture taker's museum, everything's crowded in all sorts of ways and the lighting is dark in many places. Many unique pieces, and seeing some of the actual, specific aircraft that did something noteworthy is cool ( Bockscar anyone? Bendix trophy winning Hustler?)
It's a bit much though, after about five hours I was ready for the end, I only need to see so many variants of F86 Sabres in a day.
But at least I've seen the Valkyrie now.
Oh yeah, watch out for little school-heathens on field trips.