Great film - and I would recommend getting this 2006 release which is an extended cut (137 mins) and includes 11 'featurettes' (each 2-5 mins long): these give a rare insight to the thinking behind and making of the film. I just bought/watched this version and thoroughly enjoyed it. The 2001 'Superbit' release would only make a difference if you have a home cinema; you would have the original 127 min version with this and no extra features.
The purpose of the rock music score and modern mannerisms used by the characters is to make them believable, so that the viewer is drawn into the film - this would not happen if pure 1300's language were used. The film starts as it would in real life if you came upon a group of people you never knew - you'd get to know them as time goes by; no need for lengthy 'character introductions', all is revealed as the story unfolds.
Quirky, passionate, amusing, the story links with history by its references to Chaucer and characters in "Canterbury Tales". It is described by one of the cast as a "romantic medieval jousting comedy", which just about sums it up! And when you discover it was filmed in the Czeck republic, including homeless people as extras, it adds to the poignancy of the film.
It is rated PG probably because of the jousting scenes which are pretty vivid and done for real, as the featurettes explain - they may be balsa wood lances, but a 40mph collision still hurts; the violence and 'romance' is otherwise carefully filmed and not OTT. The only person who dies is the opening character, clad with armour, who is already dead; and all ends up happily ever after. With visual detail, verbal banter and great characters, it's a great family film with something for all ages... unless you suffer from a sense of humour deficiency.