I went to see John Carter on opening night and I'm glad I did. I admit, I'm not really an Edgar Rice Burroughs fanboy and have never read A Princess of Mars, the book upon which the film is based, but I do know some of the details of the world of Barsoom. Because of this, John Carter hits the sweet spot for me, midway between a hardcore fan and a total neophyte. I can't say how true the movie is to the original, but given the source material is a century old and it is Disney that made the film, I do not doubt some liberties were taken for the benefit of modern moviegoers. Nonetheless, the movie is very enjoyable and will no doubt satisfy all but the most hardbitten purists.
That's not to say the movie is flawless. Canadian actor Taylor Kitsch, starring in the title roll, makes no effort to sound even remotely like a Confederate soldier despite repeated mentions of his Virginian roots (including a bit of a running joke). This is probably for the best, since a poorly-executed southern accent would have very likely been worse than none at all. Also, in an effort to portray Mars as a dying world, the landscapes are universally desert. These vistas are truly beautiful and stunning, but given the presence of so many peoples (Red Martians and Tharks) and fauna (giant white apes, riding beasts and weird, super fast salamander-dogs), the absolute absence of even a single blade of grass leaves one wondering how anyone finds enough to eat. Finally, I found some of the feats of strength performed by the lead character to be a bit over the top, more akin to Neo from The Matrix than an Earth human in a low gravity environment.
Still, the movie is a visual feast, with competent acting and good pacing. Best of all, it's not stupid, which by the standards Hollywood typically sets for itself these days, is an accomplishment in itself.
Oh, I almost forgot, the movie is 3D and happily, the 3D effects are well done. No post-production 3D-ification here.
Update: Ok, apparently John Carter was not originally shot in 3D. I'm surprised, having seen some really crappy 3D effects (Clash of the Titans, anyone?). I may have to seek out a 2D version of the film to compare. I don't need much of an excuse to see it again.