I was slightly duped into seeing this, and it wasn't what I expected. In fact when they started singing in the second minute there was quite a lot of giggling and surprised faces in the cinema. It didn't help that one of the first voices is the cockney boy, who like all cockney boys is a terrible character. I preferred the preppy American Little Red Riding Hood, who along with Chris Pine's over-the-top Prince were the best things in it.
The story is a mash-up of four different fairy tales, all of which lead the protagonists into The Woods where strange and wonderful things happen. Each storyline only lasts for a few minutes before they switch to something else, reflecting the undemanding family-friendly style of the movie. There's lots of comedy and action and fantasy and deaths and cameos to try and keep you entertained. It is moderately charming, but basically I don't like kids films and I don't like musicals so this wasn't for me.
The low-point is when it nearly finishes about 2/3 of the way through, then restarts with an extended epilogue. I don't mind a long film but it's criminal to nearly stop then start again (just like The Thin Red Line and Lord of The Rings Part 3).
Overall, a painful experience.