From the 1960s through 1990s, I shot lots of Kodachrome II/25 in 35mm as well as a fair amount of 64 in 120. The 25 (especially PKM) was so much better than either version of 64 in my opinion that I begged several Kodak CEOs to offer 120 PKM, to no avail. Then processing became problematic and I transitioned almost exclusively to black and white. I've never found a color film that can hold a candle to Kodachrome 25. Today I go with digital for snapshots and anything that requires color, like magazine illustrations.
I've another connection to many of those Kodachromes -- spent more than 20 years working at the Douglas Aircraft plant in Long Beach. Even though it was officially a Boeing facility for the last 13 years I was there, we still referred to it as "Douglas." Most wouldn't even acknowledge the "McDonnell" part of McDonnell Douglas.