Basically: as a movie it’s good, solid action fare. Good supporting characters, decent pacing, nice visuals.
As an adaptation of one of the classics of science fiction it’s a work of staggering genius. The people who made this movie give the impression that they actually read and liked ERB’s Barsoom series. The plot’s not a point-to-point correspondence, but it’s a heck of a lot closer than you normally see.