I just got back from the theater. Here are some thoughts:
I'm afraid I have to agree with the general consensus that Elysium is a bit of a disappointment when compared to Blomkamp's superb debut, District 9. It starts out promisingly, but has some definite story problems towards the end, such as unclear villain motivations and an overly simplistic, somewhat unsatisfying ending.
However, there's still plenty to like about the movie. Matt Damon is great as the protagonist and his story arc works well, which keeps the movie afloat for most of its running time. And then there are the visuals, which are nothing short of exceptional. I would even go so far as to call Elysium one of the most visually impressive sci-fi movies of all time, not just in the quality of its CGI, but in its design and attention to detail. Elysium's depiction of future society comes close to the impeccable world building of Blade Runner (which is actually not that surprising, since both movies have the same production designer, Syd Mead).
I do wish the final act worked better, but I still had a great time with it as an interesting original sci-fi action movie, and am excited for what Blomkamp comes up with next.