Last week I watched "Tree of Life". Here is what I think about it:
I think it is like cilantro: either you'll like it or you'll hate it.
Some reasons you may hate it are its raw topics: grief, parenting, death. If you watch movies to escape and relax, then don't watch.
Another is "Tree of Life" parallels the story of a family with the story of the cosmos. It visually interjects cosmic events (Big Bang and extinction of the dinosaurs) and the story of a family and a boy losing his innocence. If you need action, watching the Milky Way for several minutes might be difficult to endure.
I can say that I liked it because of my demographic (30 something, parent).
The one flaw I saw in the movie was more of a question. Why was Sean Penn in this movie? His part made no sense to me, not even in the end. They could have saved 40 minutes of this long movie by taking that bit out. I see what they were trying to do, but they failed.
I was moved by this movie: moved to look inside, up, and snuggle with my kids. It is a story of redemption, just like my story, so in that way it was worth watching.