7/10. Here's why:

If you read this next comment, you'll be taking a step you can't take back because... well, because you can't un-read something. The charming and funny BEGIN AGAIN is quite similar to ONCE (also written and directed by John Carney), which I hated. It had a creative story buried underneath 3 bad elements, which this movie doesn’t have:
1) All the songs sounded too similar. Some were good; some were bad. Not all of the songs here are great or have a unique sound, but they can be distinguished from one another.
2) The musical performances were dull and repetitive. Carney also uses a simplistic approach here, but he manages to make the performances fun to watch without the need of over-editing them.
3) The amateur camera work. I know that was done to make the story feel more real, but that technique doesn’t automatically work in every movie. It’s all about how you do it. And when you combine that with the other 2 problems, it makes the movie look and feel even worse. This movie has regular cinematography and guess what: It doesn’t feel like a plastic Hollywood movie.
Whenever a famous singer is hired to act in a movie, it’s distracting. When they have to play a singer, it’s more distracting. And when they have a characteristic voice, it’s as distracting as a moose wearing a hat inside a house. Didn't someone teach it manners? Therefore, it’ll be hard for anyone to pretend they’re not watching Adam Levine on-screen. That being said, his performance is OK. Meanwhile, Keira Knightley and Mark Ruffallo are at the top of their game. The romantic aspect that isn’t really romantic was confusing from the start, but it all made sense by the end. At the beginning, I didn’t buy that GRETTA would agree to work with DAN based on her first impression of him, specially on the same day of her break-up. Then I saw them talking and they actually got along. Then they walked around the city in what seemed to be a date, but I thought it was weird that he told her that he had done that with his ex-wife. Now I realize that he was making it clear that he didn’t have feelings for her. He may be a drunk and all, but he’s a professional. So when the movie was ending, I could feel it and I realized that they weren’t going to get together. And I had made peace with that. After all, there weren’t many scenes of just the 2 of them. And then it was all ruined with those scenes shown during the end credits. They felt like a last minute addition after a bad test screening. I’m glad that Carney wanted to show that teenage girls shouldn’t dress slutty, but why did he have to go to the extreme? I mean, in her final scene, VIOLET looks like a secretary on her first day. Couldn’t she wear a T-shirt and jeans?