Although not well advertised and distributed, this movie actually is a piece of true art. It returns to the roots of the vampire genre, but unlike Twilight or the more action-oriented alternatives, this one has a very adult take on it.
Although it has a fair share of action and blood, this movie really is not for those who expect exciting, thrilling and spectacular fight scenes. More like Interview With a Vampire, the movie concentrates a lot more on understanding these beings. Throwing some of the vampire's newborn traits away (sparkling in the sunlight eh?) and turning them into "Sucrient"-s, the movie revolves around how these creatures find their means of survival and how they deal with the price they pay for it.
Many critics say that the movie is too long and slow paced, which is true, but that's actually one of the reasons what makes it work. The scenes, the music, the characters all give you a dark, twisted, gripping and uncertain feeling. The slow-pacedness of the movie adds the sense of being lost, the sense of being empty to all of it.. which might make you uneasy, but by the end you will realize this is how the characters themselves feel like. You are made to feel uneasy, because it's necessary to be able to understand them.
...and although there are several quite good acting performances in Byzantium, by "them" I now think about Clara (Gemma Arterton) and Eleanor (Saoirse Ronan). Their characters are very different, but are also very interesting and more importantly: very well played. Saoirse Ronan does a perfect job in giving you the Eleanor whom you both understand and don't understand at the same time, an Eleanor whom you love and still are afraid of. Then there's Gemma Arterton who brings her best performance ever to the screen, giving you a cruel, wicked and wretched Clara who soon turns out to be so much more than what they call her...
There are quite a few vampire stories out there already, yet Byzantium achieves to be a unique pearl among all of them. Its dark feeling, interesting characters and slow storytelling do require a specific audience - people who like to listen and be mesmerized. If you feel like one, Byzantium is a must-see for you.