It's definitely one of my new favorites. I'm of the opinion that The Fountain is Aronofsky's best work to date. It's almost as if everything that went wrong with Pi was fixed with The Fountain. As has already been mentioned, the techniques used in lieu of CG are fantastic and the effects come off spectacularly. The storyline isn't lacking, either. I tear up quite often in movies, but I wasn't alone this time!
One thing I have discovered, however, is that it seems like people either love it or hate it. When people announce that they can't stand it, those who can't get enough often accuse the others of simply not being able to understand it. Which, of course, just leads to an escalating argument about who is smarter than the other. But regardless of the plot (and I do know people who said, "I don't get it..."), I just don't see how people see it as anything less than a masterful work of art. The blending of mythologies is fantastic and the presentation does what many other "choppy" films fail to accomplish.
The only unpleasant experience I have in connection with seeing this movie is that some cow sitting in front of me decided that she didn't like the movie and thought that everyone else was of the same opinion. So she had no qualms about turning on her cell phone and calling her friend to tell her how terrible she thought the movie was. This was maybe half an hour into the film. I kicked the back of her seat and my friend cleared his throat a couple of times, but she didn't hang up until he said (loud enough to be heard by everyone), "Holy shit! Is that lady talking on her phone?!"
At any rate, I wish it were still in theaters. I can't wait for it to come out on DVD. If you haven't seen it, find a theater that might still have it.