The atomic testing museum is fascinating, and information dense experience. The Area 51 exhibit is quite silly however, and I wouldn't bother with it if I had my time again. It detracts from the serious museum next door.
Once inside the museum you are taken through the history of the US test program from Trinity onwards. The exhibits are thoughtfully laid out and there is a lot to see, we especially liked the theatre that was set up to recreate watching a test firing.
The museum takes the point of view of those conducting the tests and I didn't see much information regarding their unintended consequences.