They missed important parts from the book. I know this sounds a clishe, but I've watched the series first and then read the book and then understood key points of the plot that were rushed if not even ignored in the series.

We know that the creative department always tweaks book stories, but, especially for a storyline that for its most part unravels in a three weeks time, the sub-stories of some characters stole time for the main characters to establish what's going on and their storyline felt more pushed than most of the Vampire romances I've ever watched. The sub-plot where fine, but didn't need that much time to be understood.

The series end differently from the book and I'm curious to see where they'll pick up the story in the second season, hoping that they'll make it more complete in terms of storytelling. This one definitely has "rushed" all over it, although it had a great potential due to the historical tone of the source material.