For a movie that was made almost 50 years ago, it holds up incredibly well in terms of its appearance and doesn't look any older than some movies from the late 80's. With that being said, Sssssss is not particularly scary unless you have a great fear of snakes. It's a mildly entertaining movie, but probably not memorable enough to command repeat viewings.
What did you think of this movie?
(http://fight-evil.com/movies/s/sssssss-1973/1.jpg)
Like I said in my review, it took 30 minutes into the movie for me to realize I've seen it before. It's not a terrible movie, it's just not all that memorable, especially when there are so many great movies from the 1970's.