This is a very powerful movie. I have never been a big fan of Jim Carrey, but in this movie he is great and plays the character with much sensitivity apart from humor. Apparently the movie was never a big success in the US, which could be because the subject is too close for comfort.
It brings to mind the story by Gurdjieff of the evil magician, as the movie shows how Truman is really not in control of anything, as it is all orchestrated from above. Just like we like to think we are at the top of the food chain and in control of our lives, so too does Truman believe that he makes real choices and that he is free. Little does he know that he is lives in a "cage". To keep Truman from discovering the Truth, the "media" is employed to constantly shape his opinions and to suppress any questioning of the reality in which he lives. This has scary parallels to todays world, where the mainstream media and manufactured opinion polls acts like the ancient Greek chorus in shaping public opinion the way the controllers wish it to be.
So definitely a top movie, that won't disappoint. It is a wake-up call to question one's own reality and to whether one is just a machine playing out a script written by someone else.