Strong movie with two convincing lead performances.

Rating: 8/10 (17 October 2014)

(Also don't read this if you want to avoid spoilers for "Once".)
"Begin Again" was written and directed by John Carney, responsible for the wonderful 2006 music movie "Once" and here, with a much more prominent cast, he did not let me down either. This movie was originally intended to go by the title "Can A Song Save Your Life?" and I'm glad they changed it, as admittedly it did sound a little pretentious. "Begin Again" fits the story very well too.
The first half has many leaps in time, so we see how Ruffalo's and Knightley's characters meet for the first time from their own perspectives. I liked that a lot. What I also liked was Knightley's singing, especially in these scenes when there is no orchestra or band playing. Something raw about it! Back to the scene where they meet for the first time (or I should probably say where she sings and he listens): He had a few drinks before and imagines her voice going together with a full orchestra. This was possibly the highlight of the whole movie for me. Really well done and it left a lasting impression. I wanted to swing with Ruffalo's character there.
Now that I mentioned my favorite already, here is some more scenes that I deemed significant:
The ending was expected, if you have seen "Once". It seems a bit of the director's trademark to pick something that the audience will not totally love, but understand. You wonder during the whole film if they get together (it probably even looked more that way in "Once" than here). I have read different interpretations here, but my thoughts were that Levine's character played the song the way she wanted him to and she sees how the audience loves that version and is deeply impressed. Obviously, we see Ruffalo's character getting together with his ex-wife again and it seems like Greta makes the same decision.
One indicator is the ear-phones she sends back, which is a bit of a sign that at least their romantic relationship is gone. These played a major role in an earlier scene, where they connect by sharing their playlists and both listening them at the same time by sharing the earphones just the way Ruffalo's character did when he met his wife years ago. In the end he sits on a bench back together with his wife and these two sharing the earphones. Earlier there is a scene where he gets in a car with Greta and the wife (Catherine Keener) looks at him through the door. Later on, it is exactly the other way around. Ruffalo's character gets in the car with his ex-wife and Greta looks at the two. Nice parallel here.
Adam Levine, I'm not really familiar with his music except one or two songs and I would not call him a particularly gifted actor after watching this one, but the part seemed good for him. He gave a credible performance.
What stayed in mind was the Jerry Maguire quote from early on. These two are not completely the same, but actually there are a few parallels. I won't go further into detail here in order to avoid spoilers for a third movie.
Hailee Steinfeld was not a highlight here. She gave a wonderful performance in "True Grit" and is possibly the most talented actress under 20 right now, but her character's development was just so predictable just like the whole transformation that came from her bonding with Knightley's character. She looks up to her, dresses differently and evolves character-wise, but there was nothing fresh about her storyline. It has all been done many many times before. She made the most of it, but I felt she was a bit wasted here.
Another scene I really loved was the moment when the two central characters really make a connection, namely when Ruffalo's character tells Knightley's character that it was his wife who cheated on him. The hug from behind is one of the most beautiful shots of the movie year 2013.
Other than that, there were quite a few record label references, which I did not find too interesting, but if you are more into the actual physical creation of music, you may disagree. I liked seeing Mos Def again though, eight years after his excellent performance in "16 Blocks".
A negative point would be the inclusion of police (rooftop, metro station). I did not really like how they used it to show how the central characters were so alternative and just did what they liked to the level that it was illegal. No need to bring that in. It just seems forced to make them even more likable, but the two already were anyway.
Greta's platonic friend was played by James Corden. Random note: He will replace Craig Ferguson as host of "The Late Late Show" in 2015. Solid performance, nothing outstanding. I liked how he was the polar opposite to Adam Levine's character: a street musician, neither rich nor famous, but completely authentic. Another interesting snippet is how both men (one early on, one at the end) ask Greta to come to the stage and sing and she only did it for Corden's character.
There is a reference to alcoholism included too, but this is not what the movie is about, so I liked that they did not go further into detail. Had they elaborated on it, it might have left a more serious aftertaste that could have hurt the overall picture.
For the most part, everything worked very well and with the exception of some very minor criticisms (Ruffalo's speech against Levine's character at Greta's apartment felt to self-indulgent, Levine risking a longtime relationship with Greta for Mimi not too credible). In the end, this is not really a love story, but much more about forgiveness. However, the most important thing here is the music of course.