I don't normally trust metacritic/rotten tomatoes much for their reviews.
There are a lot of reviews that are used to accumulate those scores, and a quite often the individual reviews can seem to be quite awfully written, or rather, the things they criticise are not worth the criticism.
There's also a lot of critics who seem to just have a disdain for superhero movies because of the sheer volume of them.
I would listen to a metacritic/rotten tomatoes score, but then go and see the film yourself.
Critically bad films can be amazing, and critically good films can be boring yawn-fests.
I'm looking forward to seeing it. I will just be happy to see an 18 rated superhero film. I have enjoyed most of the Marvel Cinematic Universe, and the X-Men series, but it's so tame given the plots they are playing with, that I find myself bored of it.