You may wanna be careful spoiler-wise; at least with the PopCultureNerd review: the Q&A is rather light -- but the review certainly isn't. Also from this one, prepare for a sober, rather analytical assessment of the movie, which may affect your expectations. To even this out, I have also added an early review by Anne Thompson of Variety, who makes sure to declare, she were "not a Fincher kool aid drinker" -- which is what all of us probably are! Anyway, she didn't like "Se7en" and "Zodiac" too much, but does seem to have found quite an enjoyment in watching "Benjamin Button".
Since I will not read the screenplay before I see the film (and obviously haven't seen the film yet), I cannot evaluate the specific points these reviewers are making, even though they both do seem thought-out and reasonable.
Take them as two early opinions. After all, one of them is not an excessive kool aid drinker and the other is a pop-culture nerd!