This is an uneven film, and there's lots wrong with it, some of which has been mentioned by other reviewers.
Rather than rehash all that, what I wanted to mention was the naturalness that Moore sometimes brings to her musical performances, a naturalness that makes them very engaging. The most notable case is probably Ciri-ciri-bin, where you can actually imagine the restaurant crowd joining in, so unpretentious is the whole thing. Some of the opera excerpts have that same quality, at least at times.
Some of that comes from Moore's stage personality, which at times does come off as the girl next door. Some of it, however, comes from the fact that her voice, at that point, was rock-solid and capable of remarkable things. In many ways, she was like a female Mario Lanza: she had the raw gift, she just didn't always put in the necessary work to bring it under control. Nevertheless, she goes sailing through some of her numbers with clear joy because she knows the notes will be there.
As I said, there are lots of problems with the movie. At times, her character seems like an interesting feminist willing to sacrifice to have a career. At other times, that all goes out the window.
The music is good here, and some of the performances at least partially captivating. Not a great movie, but one worth watching, at least once.