Saw it yesterday, was kind of disappointed. Was thinking how long it took to get to multiverse stuff and how little multiverse stuff actually happens. They spent most of their time in one alternative universe, not like they are hopping through a dozen which is was what I was expecting. Also, when I heard it was going to be fan-service and cameos, I was expecting a hint towards the Fox Men Universe (besides a single actor). I had not seen any trailers or looked at any posters beyond a glance. I guess due to the title "Multi-verse of Madness" I thought there'd be one crazy thing happening after another beyond the Dr. Strange vs Wanda story. I was hoping to see something going way beyond what No Way Home did and seeing tons of universes and maybe even a Hugh Jackman appearance. The movie turned out to be pretty small-scale all things considered. Not that this is a problem but after what happened in Spiderman this isn't really doing anything too crazy or exploding minds audiences or anything.
Also, I remember the Dr. Strange actor saying to an audience that this was going to be the first "dark" MCU movie and the audience went nuts. I thought it was stupid to indicate as such and I'd prefer to never have read that, since it probably influenced my expectations. Outside of Wanda gruesomely killing some alternate superheroes, I didn't think it was THAT dark, certainly not more so than some moments in Infinity War. I also don't see this as a "horror" movie at all. The dark and zombie elements are closer to "Hocus Pocus"-style horror than a proper horror movie. You can't keep the funny-quip-every-minute MCU style and maintain the "dark" and "horror" style at the same time. For those that watched New Mutants (which I thought was alright despite the reviews), THAT was much more of a dark "horror" superhero movie than this. Chronicle is another good example. Neither of those would have properly kept their dark tone if MCU-style humor was sprinkled throughout. Something has to give, either the movie maintains the MCU funny stuff or truly goes in a different direction. Compare Deadpool to Days of Future Past, both of those movies picked a direction and stuck to it.
I think the above made the movie felt disjointed at times. Like on top of trying to get a good Dr. Strange vs. Wanda story, it was supposed to be multiverse fan service, Raimi "horror", etc...
Then I saw it again today and had a much better time with it. I saw less as a Spiderman multiverse followup and more of a simple battle between two wizards. I think it still feels a bit disjointed and the pacing is nothing like the perfection of Infinity War, but overall it's a fun movie with cool appearances by alternate superheroes. If they had kept the name "Multiverse" out of the title and if I had never seen them trying to sell this as "dark" and if I hadn't seen Twitter predict a ton of fan-service "cameos" I would have enjoyed it a lot better.