The missus and I, having just read (or re-read in her case as she's been a Barsoom fan MUCH longer than I) Burrough's Princess of Mars in time for the premiere, caught a matinee of Stanton's John Carter this afternoon.
Overall, as a piece of fanservice, I liked it. It was close enough to Princess (though the major antagonists evidently originate from Gods, which I haven't yet read) for the diehard canonite in me, with lots of loving references, that I can more or less overlook the necessary plot constraints and changes. I attempt to have more of an open mind to book-to-film adaptations and, as long as the spirit is retained, I'm willing to accept and play along with even drastic plot changes (see Two Towers, which was my favorite of book and film trilogy, despite being the most different from its source material.) So, as a fan of Barsoom, I was more or less pleased with the movie and enjoyed seeing several scenes and characters (Woola, especially) visualized*.
As a screenwriter, I was less than impressed. While it had a few well-structured scenes, particularly in the beginning, as the film progressed it fell into several big, unavoidable blockbuster tropes, including shapeshifting villains, an over-convoluted climax and the messy emergence of surprise morals in the protagonist, previously possessed of few. I do honestly think (as he is in the book) John Carter works best as a dumb old boy from Virgina with a mean right hook and not much more to write home about. Making him a bad boy who speaks Apache and has a dark past in which his village was burnt felt unnecessary.
The film also suffered from an attempt to over-compensate the female love interest, Dejah Thoris, from the lilting beauty she is in the novel into a hard-fighting, brilliant scientist bombshell. In all honesty, she made Carter, the ubermench from another planet, look a little underwhelming. Her performance was the most redeeming part of her character but, in general, I think she fell too short.
In summary, if you're a fan of Barsoom, see it. If not, probably a pass.
*Tars Tarkas, my favorite character, was pretty severely emasculated as well, what I consider to be the real crying shame of the picture. The book describes him as literally the greatest Barsoomian warrior living, a seventeen foot tall colossus who easily dispatches all who stand before him, whereas the film has him trounced in practically each action sequence, particularly by Tal Hajus, his ancient rival and (at least in the film) noted glutton and pervert. And finally, when Tarkas' moment for glory comes, Carter unnecessarily fills the roll and slaughters the Jeddak himself, as if bringing down a mated pair of white apes less than sixty seconds ago wasn't enough. Cut a Thark a break, man.