Summarize the following movie reviews:

1. A film that sparkles with many gems.
2. One of those films that create a mix of erudition, pageantry and delectable acting opportunities, much as Shakespeare in Love did last year.
3. Mike Leigh's great big, superbly performed homage to the creative process.
4. A loving, gently funny and slightly claustrophobic tribute to theatrical life.
5. A hive of broad, brilliant performances.
6. Just watching this film offers its own rewards.
7. Musicals adapted as films don't get any better than this offbeat one.
8. Despite its draining length, it proves to be even better and richer on a second viewing.
9. It's an extraordinarily entertaining piece of work.
10. Admittedly, at 160 minutes, it's probably too much of a good thing. But, given that so many of the film's scenes consist of productions of Gilbert & Sullivan musical numbers, who's going to complain?
A thoroughly entertaining character study and a great success for Mike Leigh.