I watched it over the weekend. The animation is top tier and so is the blu-ray presentation. I really enjoyed the level of quirky detail and imagination in the character designs.
The plot is pretty straightforward once the movie gets into it but there's a certain level of disturbing, almost surrealistic sadism throughout that I would warn parents of very young children to perhaps check this movie out on their own before letting them watch it. One character has an arrow through it's eye, one character is basically roadkill while giving Rango advice and several characters suffer (bloodless) deaths from large falling objects among other things. It's all handled in a cartoonish, almost Merry Melodies-sorta way but the amazing level of detail in the animation adds a very strange feel to such proceedings. Let's just say this movie has a harder edge than any Pixar film.
Overall, I liked the movie a lot, but the harder edge and the occasional lapses into an almost druggy abstract mode of storytelling (even Hunter S Thompson makes a brief cameo) that often just seems to be padding time without advancing the story to the point it may lose both kids and adults.