I haven't read the Barsoom books yet, so I didn't have fixed expectations, beyond the knowledge that ERB's John Carter is father to Buck Rogers, Flash Gordon, and Superman, and grandfather to the Star Wars franchise.
The movie delivered thrills and a visual feast. Yes, we've seen a lot of this before, and Shakespeare "is just a lot of famous quotes strung together".
It's refreshing to see a Mars that isn't constrained by a tedious pretense of "realism" -- there's neither need nor attempt to reconcile Barsoom with NASA's description of the red planet. The imagination is allowed to soar as high as Carter can jump.