Daybreakers brought a new dimension to the appearance of vampires as the ultimate predator and offered a good look at corporate greed and the real cost thereof.
The downfall? There are plenty of loop holes, little side notes, and inconsistencies; as well as sone incredibly campy and often times ridiculous humorous points that seem to have been meant seriously.
A good movie, while I haven't read the book, from what I've gleaned off of others whom have, it stays relatively true. Granted, like all movie adaptations there are things that just aren't here, but they didn't seem to detract, and thankfully there was very little left unexplained or just picked up half way along.
For a movie based on an old cult classic, Star Trek really held it's own. Utilizing a lot of the old, near comic, lines and a strong cast, it managed to stay true to what Star Trek always has been without simply recycling storylines that were already written ten years ago.