Currently, most reviewers are comparing Joker to early Martin Scorsese movies such as King of Comedy and Taxi Driver. I think there’s a better comparison to be made, however.
I remember reading the reviews for Fight Club during its initial release in 1999. I loved Fight Club, largely because of its honest, deep-cutting message on the then state of our society. I was surprised to read some reviews that referred to this brilliant film as some critics called it "irresponsible and appalling." Today, there are similar reviews, saying similar things about Joker.
I saw Joker last night, and haven't really stopped thinking about it since. (Except for my dreams last night which had me hanging out with the cast of The Brady Bunch, trying to hook up with Marsha.) My point is... History has proven those reviewers who panned Fight Club to have been wrong. Joker is CLEARLY excellent and plainly thought-provoking. It's hard to argue that it isn't. So, dumb dumb reviewers who are panning it, may I present two pictures. Please note the disparity between the critical and audience scores, you very wrong and very dumb dumb dumbs.
Anyway, yeah, everybody else... go see Joker. High quality movie.