Just watched it. My short review:
Like all Nolan's movies, it looks fantastic. In fact, I would say that visualy looks better than any of Nolan's movies (which is a pretty big thing). The acting from the main actors McConaughey, Chastain and Hathaway is very good (especially from McConaughey who is one of the best actors in the world). The idea of the movie isn't revolutionary, but is interesting. The movie is emotional on many parts, which was good considering that since Prestige I found Nolan's movies very cold. And lastly, the music is really good. Hans Zimmer is the best when it comes to this.
Now the negative part. A big part of the movie is a shitload of nonsense. While on Inception, you needed two hours after the movie to realize that, here you realize it instantly. Really some parts are just stupid. It has all kind of cliches, and it is extremely predictable. You can see the influences of 2001 and Tarkovsky movies, but it hasn't been implemented that well. I also found a scene very similar to Armagedon. Also, why on Earth they needed to put an antagonist on the movie? Similarily to Prometheus, it was completely stupid.
To conclude, it is a decent movie, a lot of fun but ultimatelly nonsense, lot of cliches, predictable and non-revolutionary (like it was hyped to be). Would say that it is somewhere between The Dark Knight Rises and Inception/Batman Begins (on quality) and far below the likes of Memento, The Dark Knight and The Prestige.