Yes. And so did Orson Scott Card, the author of the legendary sci-fi novel "Ender's Game." On his website he stated that he's repeatedly turned down offers to adapt the story to the screen, fearing the story would be butchered. But he said Serenity is what he'd want if he ever let his story be filmed.
I can't conceive of any legitimate criticisms one could make, aside from some plot/story decisions which I won't reveal lest I spoil some spoilers.
Diff'rent strokes, I guess, but unless you have an aversion to Whedon's unorthadox syntax and odd jargon I can't see how anyone could criticize the writing nor the dialog. Serenity towers over most sci-fi films of the last decade, and certainly smokes the lousy Star Wars prequels in every way.
Any fans of the series simply cannot miss this one. Nor should any fan of good movies in general, even those who normally don't care for science fiction.
