Zero spoilers in here.
Absolutely wonderful. I can't do a big braining on what everything means in this crazy topsy-turvy roller-coaster of a movie, but it's one hell of an entertaining ride if you just sit back and enjoy it. For me, this movie needed to be watched the same way I watched Lost Highway - don't try to understand it, just be open to being frightened and entertained.
Suffering from generalized anxiety myself, the first part of the movie is absolutely brilliant, showing the world through the lens of someone with a severe case of anxiety. Everything is over the top, and the attention to detail is stunning.
The movie devolves further and further into madness, somewhat akin to the way it did in Mother, except not in a frustrating way, but rather an action-packed and crazy, sometimes touching way. Oh, and hilarious. There are such funny moments in this movie, often absurdly so.
I didn't read up on anything before watching this movie, and I had no idea it was going to be three hours. I didn't know Ari Aster made it, and frankly I didn't know who he was. Looking it up afterwards, I see he made Midsommar, which I found tedious and boring, and Hereditary, which I absolutely loved.
I can definitely see how someone could hate this movie. I can also sympathize with being frustrated with it if trying to understand everything. I think the best way to watch this is popcorn. Watch this like you'd watch a popcorn flick, except expect absurdities instead of explosions (though we do get explosions here, too). That's how you'll be entertained by this amazing movie. I'll be watching this again.
Oh, and Joaquin Phoenix deserves an Oscar for this performance. Absolutely his most impressive performance so far.
Watch this. It's special. Even if you hate it, you won't regret watching it.