I give Black Adam a solid 7 out of 10. It's the same DCU as Suicide Squad and Shazam, so there are a few kinda corny moments in the beginning, but once the fighting started I was pleasantly surprised. Dwayne Johnson comes off as a very believable anti-hero, and the supporting cast, which I had no idea includes Pierce Brosnan, were really good. It helps if you have already seen Shazam, because they don't really explain the Council of Wizards in this movie, so watch Shazam first if you haven't seen it - it adds a lot of depth to the plot.
And the after credits scene is, while not completely unexpected, was still pretty cool.