I like letterboxd more personally, because i think their overall rankings and average ratings are better and thew user reviews are way funnier, but there are some things I like better about IMDb.
For example, i like how IMDb scores are formatted on a 1-10 scale with 1 decimal point vs letterboxd’s 1-5 star system(i.e. 8.8/10 vs 4.4/5). In fact, everytime i look at a letterboxd score, I just mentally multiply it by 2 and think about it that way.
Secondly, IMDbs method for listing actors in a movie is way better than letterboxd because they actually list what character said actor plays in the movie and shows a picture of them. It’s genuinely impossible to see who played what character on letterboxd
I would say Letterboxd but it seems like so many review sections have become power users just spamming really witty one-liners and it's hard to find decent reviews. I find myself gravitating toward IMDb more and more.
For example, i like how IMDb scores are formatted on a 1-10 scale with 1 decimal point vs letterboxd’s 1-5 star system(i.e. 8.8/10 vs 4.4/5). In fact, everytime i look at a letterboxd score, I just mentally multiply it by 2 and think about it that way.
Secondly, IMDbs method for listing actors in a movie is way better than letterboxd because they actually list what character said actor plays in the movie and shows a picture of them. It’s genuinely impossible to see who played what character on letterboxd
My main gripe with it is basically what you mentioned with it being a 10 point system. Personally I'd rather a 20 point system.
On Rotten Tomatoes, neither the audience ratings nor the critic ratings seem great.
The audience ratings are always like "100% fresh - Superheroes with Capes 7".
And the critic ratings are like "100% fresh - 3 hour long movie about a girl and her complicated relationship with her psychiatrist".