Watch the movie with an open mind.
It's a great watch. It's very different from the previous MIB movies but in no way is it bad. Chris Hemsworth and Tessa Thompson share amazing chemistry, I really enjoyed the humour. Kumail Nanjiani is amazing.
To the people complaning of a feminist agenda, having a female character doesn't make your movie feminist. Saying maybe we should not be just "men" is black is not the feminist agenda.
Every MiB movie was political with a lot of subtext and so is this.
Coming to the plot it's more engaging than the second MIB movie but not as intense as the third. I say this to give you a scope.
The great thing about this movie is that it isn't riffing or imitating the older one's. It's its own thing. It's paced different and has a different tone. There's no way it would pull of that nostalgic charm of it tried to anyway. This movie was a great watch and I hope to see more of it. The onslaught of bad reviews feel like whiny old fan boys.
Watch it with an open mind and give it a chance. It's fun and I enjoyed it.