Call me lazy, but I really don't know that I can actually write a review of this film.
Simply said, "Synecdoche" should be seen if only so that you can make your own judgment on the film.
I personally liked it, but by the end I was completely emotionally and mentally drained. I still don't feel like I have completely wrapped my head around it. I'm not entirely sure that five more viewings would change that.
It is completely unlike anything I can think of, and it's a helluva trip into the neurotically warped mind of Charlie Kaufman. But it is not an easy watch.
I did get the sense early on that upon having his first trauma to his head that the film might be going into a dream realm, but there was little to no evidence to support that by the end of the film past the growing sense of surreal neurosis that began to envelop the film.
I really think I am just not smart enough to decipher the film's meaning upon one viewing.