Having been a frequent patron of both while living in DC: my opinion is that the Udvar-Hazy center has a much better collection, but I'd argue the NASM on the M

Having been a frequent patron of both while living in DC: my opinion is that the Udvar-Hazy center has a much better collection, but I'd argue the NASM on the Mall is the better museum. There's a lot more information and things to learn versus just relying on the presence of artifacts. I felt that I had to take a guided tour at the Udvar-Hazy center in order to get the full experience.