This is definitely an interesting take on vampires. They make sense, they're reasonably well explained and they rather fit into the world, or at least some of them do. Neither the properly dreadful beasts of old nor the very differently dreadful modern take, Martin's vampires are refined ultimate predators that, like humans, can choose to use their abilities for good or ill, and in the end to obey or rebel against their rulers, however powerful they may be. In many ways, it can be said they're similar to Anne Rice's, but in some other notable ones they're different, plus that this book was published when only Interview with the Vampire was out and a certain other series of hers was quite some years away, which rather limits the odds of that being the inspiration for many of the elements seen here.
Otherwise, Martin was Martin even back then, with his detailed descriptions and explanations... Including of food, of course. Sadly, this book has an extremely narrow focus which impacts not only the way in which the world is portrayed but also the characters, as all but a few are developed poorly, if at all, and have little actual impact or significance. You'll be able to "see" and, if you're so inclined, properly understand everything the author deemed crucial and, depending on preference, either trudge through or delight yourself with quite a number of other little details that he for some reason liked to include, but everything else tends to get rather thrown aside with a shrug. And the final confrontation does require some suspension of disbelief.
That said, while approaching it with the idea that it's written by the author of A Song of Ice and Fire will cause people to have wrong expectations and perhaps judge it unfairly harshly for that reason, it is a very good book that I'd recommend to anyone with any interest in proper vampires, steamboats or simply good stories with limited scope. I'd have wished for a couple hundred more pages if they'd have been dedicated to the other characters, perhaps to their personal histories, and to presenting a slightly wider image of the time and place, real as it may be, but what it's intended to do, it does quite well.