It's a good movie, and I'd be inclined to see it again. Yes, there are a few things, primarily the soundtrack, that keep it from being a great movie. Apart from that, it's well acted and visually stunning. It's far more engaging than the 1974 Redford attempt. I'm no fan of DiCaprio's politics and he's had some stinkers for movies. He's also had some very strong performances and this is one of them.
Joel Edgerton gives a very strong performance as Tom Buchanan. The "Nick in a Sanitarium" gimmick certainly sounds contrived when you read about it in a review, but it works pretty well on screen, and by employing a series of flashbacks it doubles down on the whole Gatsby/Daisy theme of idealizing the past and dealing with the present.
FWIW, I've long held that, as much as I thought the '74 film was an overall bomb, one of the best casting choices in all of filmdom was the selection of Sam Waterston to play Carraway. Prior to seeing the new film, I thought McGuire was really going to have the toughest role in this film, and while I still think Waterston's Carraway was better, McGuire did well enough with a tough role; I could be wrong, but it appeared to me as he spent a good bit of time studying Waterston's performance.
Just my $0.02.
I probably will see it on video sooner or later without expecting much, and probably I'll like it more than Moulin Rouge. I don't think I could like it less.
I didn't mind the earlier version. It sort of defined the novel for me (and for other people too, though I guess we aren't supposed to admit it). It might be interesting to see a new take on the story