The association of these two movies seems quite random, and it actually is. I just happened to watch them one after the other, which is maybe why I found some (random) similarities and big differences.
Well of course I liked the French one much better, but actually succeeded in falling asleep by the end of Baz Luhrmann's last one. I can't call myself a true Xavier Dolan fan either, but Laurence Anyways I liked, really enjoyed it, even though it is almost 3 hours long. In general I would postpone a time-consuming movie like this until maybe it somehow gets lost and all those precious minutes don't get used up by a single film. But I had the luck of looking at the clock only towards the end, when it didn't really matter anyhow, because the longer it lasted, the more visually and emotionally delighted I felt.
Now Gatsby on the other hand is similarly bright and colourful, the soundtrack was also a pig part of the project and it is a love story as well, but in comparison it felt cold and it got me wondering what other more useful things they could have done with a large portion of the budget, I got the sense of too much for too little. Although I enjoyed the music of Moulin Rouge! and the intention of "modernisation" with contemporary songs, this time I was not impressed. Dolan did a much better job in my opinion and the soundtrack of Laurence is absolutely memorable.
I could go on and on about Laurence Anyways, but instead I urge you to watch it. That is only if you are not a homophob. If you have those kind of reluctances, you would be better off sparing yourself the frustration.
impressions of movies that left some kind of a mark, my perspectives have a very personal character. hope others can also enjoy my peculiar descriptions.