People who enjoyed it are the same as people who enjoyed say, Star Trek Into Darkness (I saw it in Imax with five other people, one of whom is the kind of Star Trek fans who has collected editions of the DVDs); everyone thought it was an entertaining summer movie; only two people thought it was a good sci-fi movie, and only one (surprisingly, the hard core fan) thought it was a good Star Trek movie.
It's not a horrible movie, in the way that somethings are just awful and bad, full of bad acting, and painful dialogue, or poor accents, or shitty CGI, etc. But it is technically marred by poor editing, and the people defending it and even saying the editing situation or the over-stuffed stuff is cleaned-up by an additional 15 some minutes of film are simply kidding themselves and others. The technical problems are there and the movie has problems even if you apply comic book logic and suspension of disbelief because of source material.
I would agree that other movies that are more higher praised have similar or significant problems (e.g. AoU), and except for being over-stuffed and poorly edited, as well as the simplistic and lazy main plot (equivalent to the AoU plot, but worse than the plot of any of the Captain American movies, in these comparison), it's not Transformers level dreck.
But that's treating BvS purely as filmed entertainment (say thinking of the Potter movies or the LoTR/Hobbit movies as filmed entertainment). When you start talking about the movie as an ADAPTATION is where you have the accept criticism of it for the OOC writing/dialogue and motivations of the principal characters (again, this is hurt by the poorly conceived main plot and forced plot device/plot decisions that the principals were encumbered with IN ORDER to feed/force said stupid plot -- for example, in what universe - including alternate realities or Elseworlds, would any version of Bruce Wayne say something like "1% chance = absolute certainty?