Wall museums in Berlin?

I think the Checkpoint Charlie museum is part of the Mauer Museum, as is the Documentation and Visitor Centre. Checkpoint Charlie is sort of a one-event/location place. I would definitely vote for the Documentation Center because gives you a much bigger picture. It is on the grounds of the memorial section of the wall (puts names and faces to those killed trying to flee; we found it very moving) , gives you to visit the "ghost station" -- the Nordbahnhof Station, has a good film, and gives you an idea of the other Berlin Wall sites around the city, should you choose to branch out a bit. They also offer very inexpensive tours, both self-guided and with a tour guide. Check out https://stiftung-berliner-mauer.de/en/berlin-wall-memorial/visit/tours . But of everything, what impressed me the most were the 4 or 5 groups of high schoolers sitting quietly on the lawn learning about their nation's tragic history and another in the museum showing an outstanding respect, understanding and appreciation for what happened there. So unlike America and other countries we have visited.

If you're looking for something fascinating but a little lighter, by all means try the DDR Museum. We spent hours there. As I recall it, it small and was very crowded but made some of the biggest impressions on me and my then 25 year old son. It's an overall museum of DDR history rather than just focusing on the Wall, although there is an exhibit there about it. They cover the DDR sports machine that so dominated the Olympics and other events, and there's a reconstructed 'typical apartment, with appliances, food and other furniture and furnishings, toys, home entertainment and the like. There's also an exhibit on the internal security system. My autistic son absolutely loved the Trabant that he could jump in and pretend to drive.

we went to both museums. The Documentation Center is very interesting but has tons of reading. Not much tangible exhibits. The DDR museum is quite small but more visual. In fact, my husband grew up in the old Yugoslavia and had many of the items in the museum. In fact, we could donate items to the museum from his parents' apartment.

I think the name of the first place you mention has been tweaked since I visited it in 2015. I found it fascinating. There was a heavy focus on escape attempts. It's a more casual place than the Documentation Center; I think it is privately owned. I believe you'd find both worthwhile, but there is so much Cold War history in Berlin that it's hard to find time to see everything.

Also worthwhile are the Palace of Tears and the Stasi prison, Gedenkstätte Berlin-Hohenschönhausen. The latter isn't in central Berlin, so it's more of a time commitment. They have a film and offer tours; there's some overlap between the tour and what you learn from the museum-like displays, so it would be more time-efficient to take the tour first.

Two good movies about the Cold War period in Germany: The Lives of Others and Balloon. Balloon is currently available from the free streaming service Tubi.

I second the suggestion to visit the Palace of Tears, it struck me closer to home than the larger wall exhibits, though I did enjoy the Documentation Center (especially walking in the outside exhibits). I also did a walking tour of the east side gallery (with all the murals painted on the wall) which provided a lighter counter point to the subject.