To offer a second opinion, the Cray-1 was the only thing I found cool about the Computer History Museum in Mountain View. It was otherwise just a like a big website, the history was all dead. In contrast the National Museum of Computing next to Bletchley Had lots of computers turned on, with enthusiast volunteers demonstrating and explaining things. You could punch paper tape and feed it to the Dekatron and see the memory changing as the program ran, or poke at magnetic core memory sheets and someone was right there to discuss all the old tech.