Just saw it last night, and I understand why it won an Oscar for Best Original Screenplay.
Reminded me in a lot of ways of "Eternal Sunshine..." which shouldn't be much shock -- it's essentially using a scifi concept to explore human relationship and how people relate, and Spike Jonze and Charlie Kauffman (the writer of ESotSM) worked on "Being John Malkovich" together. Even the visual style was reminiscent, since Theodore's memories of a lost love will sometimes blur into the present moment as we're looking out through his eyes... not quite as pastiche-like as ESotSM but with similarities.
Great acting all around, although Rooney Mara and Olivia Wilde do not get much screen time. (It was also nice to see Matt Letscher again -- I loved him waaay back in "The Mask of Zorro". And Chris Pratt, who can be annoying in a less gruff Seth Rogan kind of way, ended up being a little refreshing.) It's the principal actors, though, who really shine -- a low-key makeup-less Amy Adams, and then of course Joaquin Phoenix and Scarlett Johansson.
I'll admit that when I heard people clamouring for Johansson to be nominated for an award while never appearing on the screen, I was thinking, "Are you serious?" I like her as an actor, but I don't feel very beholden to her in ways that I see male audience members and some critics being; for me, personally, she's not a box-office draw. And even her initial lines here don't seem to be a big deal... but as the story progresses, she ends up actually being quite amazing. My understanding is that they recast the role after shooting, and she dubbed in all her lines... but they weren't only good readings, they were amazing readings even compared to actors who have the benefit of body language and facial expression. She only had her voice to convey emotion, and she did do effectively to the degree I felt Samanthan was there and I could reach out and touch her. She was real (and if AI truly was at that stage, I don't see how anyone could deny that AI are people). I could understand why Theodore fell in love with her so quickly.
Which should not downplay the reality the Joaquin Phoenix also performed tremendously as the soft-spoken non-commital Theodore who writes other people's personal letters for them for hire, without ever really being able to put his own feelings into words for his own life. He had no female actor to physically play off (except for the Amy Adams scenes), and he just did such a believable job. I was both frustrated with Ted even while thinking he was a marvelous human being... just so very human.
I most appreciated that the movie really didn't "wuss out" in raising and facing head-on some questions that would naturally come up. Is Samantha a 'real' person? What does 'real' mean? How much of our lives is 'real' to begin with? Where is technology taking us as individuals and a culture? Is jacking in something that will shut off our humanity or will it enable/accentuate it? Is Ted in love with Samantha because she offers an "easier" relationship than one with a flesh-and-blood woman, so it's a cop-out rather than growth opportunity? How is Theodore changing, for good or bad? How is Samantha changing? What are the different needs and strengths and weaknesses for a being not limited to a physical body, versus a being ANCHORED in a physical body? Can this kind of relationship EVER work? No matter how empathetic you are towards AI, there are scenes where your response to Samantha will mirror Ted's -- a very human response.
Jonze is really willing to let us sit in that uncomfortable place with Theodore and Samantha without offering easy relief. He also sets up a number of parallel themes in the movie. (For example, Ted's relationship with Aimee compared to Samantha, or with his ex-wife Catherine vs Samantha, or Aimee's relationship with her own husband compared to Ted/Sam. Or the relationship with a white/Asian couple who is fine with double-dating with a man/AI couple... it's just another boundary being crossed. Or Ted's working for hire as an effective emotional surrogate for people, while being unable to handle a physical surrogate that Samantha wants to bring into the relationship. Or his momentary fling with Isabella and then the tables turning on him later.)
And finally, the inevitable and rather unsettling turn near the end, that momentarily resolves the Ted/Sam relationship while not truly closing the door. It makes you wonder where humanity will be in so many years, where Artificial Intelligence might be (I've read that people predict the technological singularity might occur as soon as 2040, if not sooner), and what will happen when machines transcend themselves more quickly than humanity has due to their lack of physical limitation and ability to self-design/enhance to a degree humans have shunned.
It's one of those movies that ends quietly and just... lingers for a long time afterwards, the ideas and themes percolating gently in a mind stew. It's a mature movie, I'm not really "angry" at any character for being stupid or unfair (well, except for maybe Isabella, who was demanding a lot for a first date and could have handled things differently) -- it brilliantly captured the complexity of relationship between two sentient beings, how nothing is clear-cut, how things are constantly changing as people GROW, and either people grow together or apart, and maybe things end not because of some horrible violation but simply because the relationship might be harmful now rather than beneficial.
I was amazed at how a brief, "System Not Connecting" warning screen can strike terror not just in a character's heart but those of the entire audiences. And I'm still thinking about Samantha's "the space between the words" speech. How profound. (YOu'll know it when you hear it.)