To me the film was a departure from what had become Nolan's style. Rather than relying on a massive, infinitely twisting plot that takes analysis and breakdown, this film had a story which invites you to think about what could be. To me that's what sci-fi should be and I was very happy with this film. I liked the story which is quite simple and, perhaps confusingly, quite linear. Took a bit of thinking to get straight everything that happened exactly, and then reading other peoples interpretations always helps. But yes story was good and at some of the quieter points I found myself thinking about the universe the film draws you into - what if scenarios etc. It's not like Memento or Inception, the film doesn't rely on a huge non-conventional plot. For me this film was more 'about the journey', like 2001, though I've seen a lot of people hesitating to compare the two and I understand that too.
Film is in places open to interpretation as to what the story ultimately means although I felt the ending almost gave 'too much' closure, which is unusual ;P Other things - music was phenomenal as were the special effects and the general cinematography was astounding. In particular the "farm -> liftoff" cut was cool. Lastly, Matt Damon popped out of a lifepod out of nowhere. Had no idea he was in the movie, so that was fun too. He seemed way too built to be a theoretical physicist or whatever he was though!
Matthew McConaughey's acting was also absolutely spot-on.
Really loved the film and am looking forward to watching it again. In a lot of ways, it doesn't really feel like a "Nolan film" and to me that's OK.