I always thought that El Dorado and Rio Bravo were essentially the same movie with just different supporting casts for John Wayne.
Wayne was a bit too old to be a romantic lead by the time of El Dorado, so they wrote out the female lead and tried to make the supporting character played by James Caan be the romantic guy. That's part of why El Dorado was (for me, anyway) one trip to the well too many for Hawks.
Getting back to the original post, I have never been a big fan of Key Largo. It's certainly a great movie, and the cast is great in it, but I just find it too nasty to re-watch. I find Eddie G's character to be too sadistic. Sadism is something I just cannot find entertaining. I don't mind bad guys, but I just cannot watch sadism.