Those who have criticised this film for its storyline have obviously never read the Old English poem on which it is based (no it isn't a saga!). Of all the film versions this is the one the comes closest to creating a coherent film out of something that is virtually unfilmable in its original form. The reviewer who wanted great battle scenes should be aware that there are no battle scenes in the original 'Beowulf'! Instead the makers very sensibly chose to omit the last third of the epic poem and therefore avoided the clunky shift to fifty years on, where an aged Beowulf fights the dragon in his homeland - which has never successfully been done. By focusing on the personal conflict between Beowulf and Grendel this film is more of a coherent unit than any other film version (if you want to see how truly awful things could have got, go find a copy of the Christopher Lambert film which is bad beyond belief).
Instead we have a film that has attempted to bring the central characters to life in the same way that the 'Lord of the Rings' films approached such characters as Aragorn - by making them more not less human. The alternative approach of going the CGI way may make for some interesting visuals, but does nothing for making the characters understandable. Gerard Butler does a great job of bringing out a hero that is approachable to a modern audience and holds the film together. Moreoever, the whole look of the film fits the period that is being recreated.
That said, it does have its flaws - the biggest being the witch Selma, who is a totally new creation. But then translating a 1200 year old poem to the modern screen is bound to need some changes! For the Tolkein fans out there this film at least gives some idea of why the original was such an influence on Tolkein in his own writing. No it isn't 'Lord of the Rings', but of all the film versions this one where at least it is possible to see the connection.