I don't know what movie the critics were watching

Rating: 9/10 (25 March 2016)

Assuming that the critics were operating in good faith (a big assumption, to be sure), then we clearly watched two very different movies.
The biggest critique going in was that the plot is a mess. I want to say right now that that is a load of horsecrap. Each scene was both coherent and advanced the plot. A couple scenes were obviously geared toward setting up the Justice League movies. Big freaking deal. They in no way detracted from the story arc of the movie.
The plot is both easy to understand and compelling enough to satisfy even the fanboys. But the real revelation in this movie is Affleck. I, along with millions of other fans, was initially skeptical that he could pull off the Batman role, but he came through, and came through big. Not only did he have the movie's best lines, but he easily had the best scenes as well. His fight scenes alone are the price of admission.
As for the titular showdown between the two characters, I have one word for it: bada$$.
I'll leave it at that.
The supporting cast also fulfill their roles, and Gal Gadot was easy on the eyes as Diana Prince. I'm not a feminist in any way, so I didn't really care about her role in the fight scenes, but they certainly didn't hurt the movie.
Bottom line: this is a very well-made film and professional critics simply got this one dead wrong. Go see it.