IGN rated it a 7.8
Now I didn't read the review to avoid spoilers and I won't post the link here because we all agreed to not read spoilerish reviews but they rated it a 7.8 and it seems like they are on the "hate marvel" bandwagon.
As of right now all 14 rotten tomato reviews have given it a 100% rating. Various sites have given it a 9 out of 10 or a solid 10 put of 10. IGN is so far the lowest score the film has gotten.
The comment section mentions how the review constantly mentioned Batman v. Superman so perhaps the reviewer himself is upset at how poorly BvS was received and how warmly Civil War is being received.