It's a bit overhyped. Not that it's a bad movie, especially compared to most MCU's entries in the past years, but still. The humor, probably, won't be for everyone, but if you liked the previous 2 films - you will like this one as well. It also does a lot of things "right" from the perspective of tending to fans. It's not just 4th-wall-breaking and cameos, no. It's the overall approach, that tries to... Honor the original source material(s). Which is what fans expect. And what made MCU so popular in the first place, and what Disney has been failing to capture.
Will it save MCU, though? Probably not. For me personally, this is a movie for 1 evening (although, to be fair, I can say this about most movies). There is nothing really ground-breaking, it does not move MCU towards anything particular (and post-credit scene is just utterly bad and pointless). On the other hand, it does show, that Disney needs to increase the quality of their movies just a little bit to make them so much more enjoyable, so here's hoping, that money will talk for the fans.