I want to say it would be my favorite for repeat viewing value. Given that the plot itself is a “reverse” Thanos character development / pseudo origin story, the Marvel Heroes themselves do not advance or progress in any way. This leaves their scenes fun to watch as they bicker, plan, huddle and all of the other “character defining” exposé needed to get none Marvel audiences as comfortably, familiar AND liking these characters that Marvel spent the last 10 years weaving stories for.
Basically, it’s a showcase of characters outside of the central plot and it makes for less “boring” repeat viewings.
It’s not the best film, however. I think that honor goes to Black Panther (as a film despite the subject matter not necessarily having the broadest appeal)
2012’s Avengers is the one I would show to anyone if they only had one film to choose.