I find a lot of people will dismiss old movies based on their age, if they are in black & white, if they can tell the monster is just a guy in a suit, etc.
Sure, a lot has changed over the years. Acting styles, methods, effects, equipment, etc. None of this means some great stories haven't been told.
I watched M (1931) last night, and I thought it was great. It got me thinking about this and how many people deprive themselves of some really good movies.