Let me start off by saying that I still think comic book themed films are being overdone. However, because of the money in box office receipts and products the studios reap I highly doubt they will be slowing down anytime soon. I didn't think that Batman vs. Superman was going to be that good, but I was surprisingly delighted with the end result of the film. So the film pretty much takes place right after the events of Man of Steel where Bruce Wayne blames Superman (along with some other people) for all of the devastation and death that has been caused since his arrival (this line of self-righteous thinking was at times a little preachy, kind of annoying) and thus he begins to go on a warpath to destroy Superman. But Clark Kent/Superman doesn't like the vigilante style of justice that Batman dishes out and decides to intervene; they clash and have a fairly interesting fight. In the middle pulling strings left and right is Lex Luthor, and boy does he pull the strings well. So after Adam West, Michael Keaton, Val Kilmer, George Clooney, and Christian Bale now, Ben Affleck dons the caped crusader's armor. Well, he wasn't dreadful, but he wasn't great either; I think he did well enough, but I don't think it was his performance that sold it. Henry Cavill as Superman/Clark Kent didn't get as much character development as his counterpart, which would have been better, but he remained the moral compass and is that boy/chivalrous man that all men deep down wished that they were. Amy Adams did well as Lois Lane, even though at times her character seemed to really lack a purpose for why she was present. Jessie Eisenberg as Lex Luthor was perhaps the most interesting of all the leading roles. He truly depicted psychotic evil in a way I've never seen it depicted before in this type of film or story; I was actually cheering against him (which isn't typical for me as I mostly cheer for the villains). Gal Gadot as Wonder Woman was great. I was actually pleasantly surprised how well they pulled off her entry since her character oftentimes does seem so over the top, but it was nicely executed, and I would have liked to see her have a larger role in the film, but what was there was good. And I do have to say that Jeremy Irons as Alfred was excellent, but that may be that I am biased since I think he is one of the most amazing actors in the world.
Now, I mentioned above that it wasn't Affleck's performance that sold the film, but rather it was Zack Snyder's direction of the entire project that made the entire film work; without him, I doubt it would have worked at all. Yes, he is one of my favorite filmmakers so there is a slight bias, but I have to say that I was impressed with the story (David Goyer gets a lot of credit for that). I don't remember ever being bored or that the plot wasn't on pace. The music by Hans Zimmer and Junkie XL I thought was awesome, and worked so well with the film (Junkie XL is definitely someone I'll be looking out for in the film composition scene). What really worked was how all of the movie was filmed. There was excellent cinematography, fantastic sound design, and rather dynamic action sequences which has been lacking from a lot of comic book films (Captain America: The Winter Soldier was one that had all of that recently). The 3-D was also pretty good, although I may be getting so used to it, or was so engrossed in the film because I don't remember anything 3-D really standing out. I think it was a well done film, and was rather entertaining. From what I hear it doesn't follow the comics as closely as some would prefer, but it is after all an adaptation, and as a writer I can attest to the difficulty to bring something from page to screen. I would see it again, and I think a lot of people would enjoy it; it is dark, but that's probably another reason I enjoy it so much; the gritty realism, as opposed to Marvel's popcorn fantasy more often than not. It should be interesting where they go from here for the rest of the DC universe.
Batman vs. Superman trailer
Batman vs. Superman interviews
Alice Through the Looking Glass trailer (actually looks quite good).