Alan Ladd was incredible in this. A very believable Gatsby, in my opinion, much more so than Robert Redford. Since it was made closer to the Roaring Twenties, this film lacks the now common air of nostalgia for that era and manages to focus much more deeply on the emotional implications of the story. IMO, that makes it worthy of a 5/5.
Seems rather lacking in ambition, skimming lightly through most of the story. Occasional particularly effective scenes stand out; Gatsby displaying his stuff (which brought me to realize that James Franco's character, Alien, in SPRING BREAKERS is modeled on Gatsby), and Gatsby's demise among them.