Try to get a good DVD-HELP!
This is one of those films that somehow slipped into the public domain at one point. Because of that, there are many DVD versions, of varying quality. The Criterion one will be best, of course. Amazon reviews tend to get lumped all together regardless of the edition.
I don't remember what I have at the moment, because I seldom watch it. (I just looked for it, and can't find it.) It's on cable so much.
I would avoid the cheapo Hitchcock boxed sets. There is a combo with The 39 Steps, and you'd have my two favorite Hitchcock films. But I don't know how it is.
Can anyone help here?