Star Wars is the best of the six films for one simple reason--it's the only one that has a beginning and an ending. Every other film in the Star Wars franchise requires you to watch the film that came before it or the film that came after it in order to tell a complete story. Even Empire, as good as it is, requires the viewer to have seen Star Wars to know who the characters are and why they do what they do, and Return of the Jedi to finish the story.
Of course, Star Wars tells a complete story out of necessity--at the time it was released Lucas and 20th Century Fox had no way of knowing it would be a hit and that sequels would be made. Regardless, it is the only film that can stand on it's own merits.
With all due respect, I don't think that is a viable criterion for what makes this (or any) movie better than another.
I think the two best arguments are, ANH was better because of what Lucas was able to do with somewhat limited resources.... vs. ESB being the better film simply because it had to follow a complete blockbuster. ESB had a ton of pressure to live up to because of ANH's success, and it delivered...big time.
I've ALWAYS ranked Star Wars above The Empire Strikes Back, even if not by much, and I always will.
This author had a few great lines that resonated with me, and describe the nonpareil genius of the first Star Wars film.
"There's a lot of talk in [Star Wars], but that dialogue is not deployed merely for exposition, as it often is in the Star Wars films, but rather for fostering a feeling of place and community within the picture. Its overall look is rougher, with less chrome and gloss, and more dirt and ash. But that griminess lends the film a mood that—despite the triumphant climax—infiltrates you, rather than pumps you up."
"But the film reveals its characters' personalities in more subtle ways, as well. People hang out a lot in Star Wars. Luke and C-3PO get to know each other in a glorified tool shed; Luke and Ben bond in the latter's hut; space chess and early Jedi training occur simultaneously as our plucky band travels from one spot of adventure to the next. We understand these individuals because Lucas had the courage to simply show them together, during their downtime. Viewed in relation to the rest of the franchise—especially the prequels—[the first Star Wars film's] restraint seems radical."
"[Many films] rely on spectacle as spectacle; [Star Wars] uses spectacle to create meaning. Its loud, splashy moments turn to foster quiet, personal scenes. After Darth Vader strikes down Obi-Wan Kenobi, we see Leia consoling Luke in a hushed, almost maternal manner that pulls the viewer into the screen as we note each gesture, each word. You start to feel like you're riding along with these characters, invested in a way that you weren't previously."
"And as much as we enjoy being thrilled by on-screen action [that moreso characterizes The Empire Strikes Back], and pulling for one side over another, there is nothing like feeling as though you've been rendered invisible and inserted into a film, relegated to stand just out of view, but privy to every breath and whisper. That's what movie magic really is, and few films put it on display better than the first Star Wars."
I always look at Star Wars and The Empire Strikes back as a coin, each with a side, neither with preference on any given day. The author put into words really well what I think most identify with in relations to the characters. You feel like you're along for the ride...getting to know them.
While in Empire, you've already come to know and love these characters so much you are revelling in their adventures, triumph's and tribulations.
I'll never be able to get over why Lucas didn't realize the magic wasn't the special effects and action, but rather the camaraderie, developing friendships and growth, adventure, and as the writer puts it "the feeling of being inserted into the film" that makes it so special. I still have PTSD from the prequals.
I gotta agree - Star Wars is the best. I don't fault folks that love Empire more and it is a great movie but my problem with it is also that it's not self-contained and on top of that, Jedi didn't deliver the wrap-up that Empire deserved... thanks of course to Lucas' Jabba's muppet palace and the ewoks.