The book was terrible, it was just a hokey chase story with the vampire mythos plugged in, it was the first to popularize ancient legends using a semi decent plot format.
The movie is much better and more enjoyable. Its fantasy so the vlad the impaler ethics is not important in this context. Secondly the move to complicate him was a good idea, one thing I strongly dislike in films is one sidedness and obviousness, I prefer shades of subtetly and character development, bending conventions rather than adhering to them. The film is a bit lumpen but then given the source material that was somewhat inevitable. It is the definative dracula movie and I don't see it being bettered as its interpretation of the source material is successfully realized and its uniqueness excludes the possibility of it being superceeded, it can only be rivalled with alternate versions.