While I haven't fully read Beowulf yet, I will be within the coming months, and I felt that this movie would give me a taste of the story. If you're looking for comments related to how the movie stacks up and compares to the actual story, you may wish to just wait for somebody else's comment.
All in all, I thought this was an adequate movie. It combined decent amounts of action, character building, and fantasy. The movie had its boring parts, like almost any other movie (Except Crank, I suppose...), as well as its high points.
**SPOILER**
One of these high points, as I would call it, is the final battle with Grendel. Not so much the slaying of the beast, but the anticipation leading up to the fight... You know it's coming, and you know someone/something is going to get killed... Probably Grendel... But you still have the anticipation growing as you eagerly await what happens next. I suppose that may be different if you're familiar with the story already, but for me it was one of the more attention-grabbing scenes in the movie.
It started off on a pretty good note as well. Too many movies these days are starting off very plain, and very boring; often with heavy music and flashy scenes to catch your eye. Personally, I prefer a movie to delve right into the story and action. Grendel does just this, as Beowulf enters a cave and slays a beast almost effortlessly. This serves two purposes, really... It gets the viewer interested in what else is to come, and it shows that Beowulf is no push-over when it comes to slaying creatures.
Though, much like I said before, this movie does get boring at points, and most of the key characters become very predictable as the movie goes on. From the moment you see Finn you know he's going to get himself in trouble as the story progresses. You know Ingrid is going to be a total ditz that gets herself into trouble as well... And you most certainly can decipher that Unferth is going to be a prick, as well as a fool.
**END SPOILER**
All in all, if you're looking for a decent movie to pass the time, and possibly watch just for a rather unique movie, you probably won't be disappointed with Grendel. That said, Grendel is unique in its own right, since it gets away from the run-of-the-mill fantasy medieval genre...
However, if you're looking for a highly original, completely enthralling fantasy medieval movie, you might want to look elsewhere; as Grendel still has many of the components of a rather blotched, horribly general adventure. You know, the easily-distinguishable CGI for the monsters, ridiculous battle scenes, and the times where you find yourself mentally yelling at the characters one minute, and laughing at their actions the next... All because of how poorly some of the fighting goes. We've all seen it, but we all still watch it.
Now, as far as why I gave it a 6... Personally, I feel the rating system on IMDb is screwed. Not because it's unfair, but because there are so many different opinions on movies, that you really have to know which opinions to follow if you're going to find the rating system useful. Without getting too far off-topic, what I mean by this is the fact that some movies you may enjoy, such as Conan the Barbarian, or The Boondock Saints, get rather low ratings, while other movies like The Godfather rank so high. Or better yet, how The Matrix beats Equilibrium...
But that aside, If I were to rate this movie with a totally open mind, based on what some other movies on here have gotten, I would give it a 6. It's better than your usual Sci-Fi Channel garbage, but not as good as some fantasy medieval classics, like Conan the Barbarian. Certainly don't expect something like The 13th Warrior here. Expect a very basic, but entertaining-at-points movie that's great to watch by yourself with some popcorn on a lonely Saturday night. Of course, if you're thinking about watching this with a group of friends, you might be better off just renting a movie from the local video store...