I watched it last night (though I dozed off a couple times and will try to rewatch it), and it didn't impress me much. Acting was good. Story, not so much. It was pretty obvious from the get-go how the overall arc was going to play out, so you just watched it for the "players" and just didn't keep me involved in it. By the time you get to the ending, you're just confirming what you though was going to happen, and there's no real twist or cool way the characters went about it.
To be fair, Amy Adams sucks. She always has. I don't know how she keeps getting roles. She's pretty unidimensional in the parts I see her in, and she's not hot enough to be cast for looks alone (actually, I'm pretty sure the minute she stops working out she's going to blimp it up bigtime - in this movie she somehow lost most of her marshmallow neck, though).
I also felt they spent too much effort trying to showcase the 70s rather than making it the environment for the story/characters.