I'm still reading this book three weeks after I started it. [Ed: It actually took 4 months total to finish the book] Right now it's taking forever to get through it... mostly because there's a lot of other stuff that I must read (usually on a deadline), but part of it is becaues it's also a very long and very Victorian novel as well, which means it packs a lot of detail in - not descriptive detail, but detail of the sympathetic kind. By sympathetic detail, I'm referring to the literary identification of the relationship between characters in Victorian novels that is revealed not through their actions toward one another, but through their thoughts and refined sensibilities.
Dracula is narratively interesting from a structural point of view. It employs multiple narrators (which means if you gloss over the section headings, which I sometimes do, you can become very confused about who it is who's speaking), and it presents their narrative view through written texts, mostly journals and diaries, but newspaper accounts are also brought in at times.
There are only three primary journal writers in the text, so everything is from their point of view, though they also report second hand what other people say they have done or felt. These reports are in addition to their own reports, which leads one to trust these multiple narrators, particularly since they reinforce what other writers have narrated before (which also contributes to its 500 page length).
There are also situations where an alternate narrator fills in what the previous one could either not know, or might not be able to be honest about. In this case, the flitting between narrators increased verisimilitude and also narrator reliability - narratoring characters aren't required to step beyond the boundaries of their own experience and personality to relay information that might otherwise be difficult for that character to describe.