Look I'm just touching on the Zeitgeist here. Yesterday was, undoubtedly, all about Star Wars. Today is — obviously — going to be all about Back to the Future. Let's debate which is the better series!
Brace yourself, I have a 'hot take' on this.
I think as a series, Star Wars has more value. It's obviously more important as a cultural 'thing'.
But, I think that Back to the Future — the original movie — is probably the best of all the movies across both series. Yep, even better than Empire Strikes Back.
But overall? I think I have to go with Star Wars.