I love books and films where the concept sounds stupid as hell, but makes a great story. Vampires on the Titanic definitely comes under this.
Mullins clearly did his research about the ship - the layout, the passengers, the events of the night of the sinking - and that means that the book is compelling and well written, as well as being gory and a unique concept. The sinking is a horror story in itself, to be honest. The vampires are wonderful creations...I liked the mix of rules they were given, especially the use of being able to turn into a smoke, which you don't see used every often these days. They are monstrous vampires too, which I always enjoy, rather than any kind of high society creature.
The human characters are compelling too, and Mullins makes the wise choice to stick to 3 main ones, with a couple of pertinent POVs popping up once in a while. I think you get the horror of both situations in this book - the horrifying, bloody lusting vampires, and the massive ship that's sinking in freezing water.
A really great read, exciting and well paced.