...Should have been the title of Disney's new film other than just John Carter. I saw the film last night and recommend it. It is good exactly in the way sci-fi spectacle adventure films generally are; in other words, its entertaining, but not something you're going to go see for sparkling dialog or deep characters. If you've read the books, you'll like it. If you haven't, but you enjoy the aforementioned sort of film, you probably will, too.
The film takes Burroughs's more rambling (if such a short novel can ramble) and episodic novel and weaves it into a more linear plot, which is largely to the good. Likewise, the script-writers update of Dejah Thoris to an action and science heroine is well done. She winds up definitely being the "smart one" in her relationship with Carter. The Green Men (a term never used in the film; they only refer to themselves by their tribes, leading many reviewers to think they're race is called "Tharks") are pretty well-realized and surprisingly true to the books in terms of culture without the film be exposition-heavy (in this regard).
There are a lot of thinks I would have liked to see done different. The opening prologue/introduction with convoluted layers of narrative, is the clunkiest part of the film. It winds up having a flashback within a flashback/framing sequence. They could have gotten all those elements in, but streamlined it. Dialogue could always be a bit punchier in these sorts of things, and the mean of some terms could have been better conveyed to the uninitiated. While the costume design or the design for the Green Men aren't exactly what I would have wanted, they turn out okay, and are really just different choices. The design of the Martian cities, though, seems to be a bit of a misstep as it's rather plain and block, and exhibits no particular sense of wonder. Faithful woola hit the right notes, but the comedy doggishness of the character could have been dialed back from "11" to a "8-9."
Still, some of my quibbles can reasonably be seen as those of a fan who would never be completely happy with any adaptation. My main point is, if your on the fence because of the negative press, you shouldn't be.