I just saw it a few days ago and it was...good! All of the actors did a marvelous job, the storyline was amusing, and the ambiguous ending was delightfully bittersweet. I went into the movie with some doubts about its performance (it struck me as pretentious), but I'm glad I saw it. I'll be sure to add it to my DVD collection once it comes out.
Now for what bothered me.
I'm not sure why people find the plot to be so ~mind blowing~. The only thing that's difficult to explain is the science behind the levels and purgatory, which is just my friend and me digging too deep into the movie. After the first twenty or so minutes, almost everything is explained about how the dream world works and is constructed. The only thing that's left on the table is Cobb's conflict with his wife and how the team will successfully complete their job.
Like my friend put it, Inception seems like the next Matrix. I can see it still being enjoyable in a few years with a fanbase that's willing to stick behind it, but it can easily get worn out from the abundance of hype (which, in my mind, isn't necessary).