Pretty good. I'd call it the stepping stone (if there's only one) between Psycho and Halloween, which kinda makes it the forerunner to most modern horror.
It's been ages since I've seen it, but I have good memories of it. No idea if it still stands up though. You know how it is sometimes when you go back to something and it's not at all like you recall?
I never saw the remake, but if anything can get me to, it'd be Mary Elizabeth Winstead. Did she get much to do in it?