I admit I went through a brief vampire fiction phase in my 20's when I hung out with theater people, had purple highlights in my hair and dressed in black. But, since I have become a mature adult I just don't see why any healthy well adjusted woman would want that sort of relationships that vampire fiction are all about.
Most of what bothers me about Vampire Romance is that it is all about unequals relationships. Almost always the Vampire is male, and super-alpha. He dominates the heroine in a way I find distasteful when I sit and think about it.
In a relationship with a Vampire a human always had everything to loose. This seems to play out in three main ways, but in with each of the basic Vampire plots the human, who is a woman in almost all vampire fiction is in a position of weakness.
The first option in Vampire fiction is that the Vampire is immortal and the heroine is human. She is prey and he is playing with his food. This is the plot in Dracula, although there are many other complications and sub-plots and Dracula isn't a Romance in the modern sense of the word. In this plot the woman is basically a consumable disposable item to the Vamp. To believe a love story with this set-up you have to believe someone can fall in love with their food. Sure I may I love Greater's Strawberry Chocolate Chip ice cream, but I'm not going to consider it my equal as a life partner. On top of that in this sort of plot the woman is always weak, inexperiences, and child like compared to the immortal vamp. Which makes this sort of like pedophilia with a mature person taking advantage of an unformed person and calling it love.
In the second basic Vampire Romance plot the main characters can stay together if she becomes a vampire. This plot basically says the only way a woman can be happy is if she completely transforms herself on every level ,and gives up her old life completely to be with her man. The difference between saying that about a regular guy and a Vampire is that a Vamp has the ability to force this transformation on his lover, it is the by-product of their lovemaking, and she will probably enjoy it. This is a variation the rape fantasy or forced seduction scenario that has been rejected in almost all other sub-genres of Romance.
The third Vampire Romance plot is the most rare. In this plot true love can "cure" the vamp. This is basically the "If he loves me enough he will change" plot that is at the root of all bad-boy, reformed Rake, redeemed highwayman, pirate with a heart of gold Romances. In many ways this is the plot I find most disturbing. It is dangerous because being fed that sort of nonsense causes women to, at lease internally, blame a husband or boyfriend's bad behavior on themselves for not loving enough. It leads to women staying with men who are abusive because they think the abuse is their own fault for not putting enough into the relationship.
There is some Vampire fiction out there that does not fall into these plot pit-falls. Tanya Huff's Blood series and Fred Saberhagen's Dracula Tapes, and Old Friend of the Family , come to mind, but although their are love story sub-plots in these series they are not Romances. I have not read Twilight but I saw the movie on a plane recently. I wasn't giving it 100% of my attention but it seemed to be a mix of plot #1 and plot #2. I'm not the target market for that book or movie but Edward gave off very creepy stalker personal space invader vibes to me.
Despite everything women have done in the past century to become equal players on the world stage even modern liberated women seem to want someone to come in, sweep them off their feet, and take them away from all their troubles. We've been told it is not PC to wait for Prince Charming, so are we turning to dark and dangerous Vampires to fill this roll? Is that OK because everyone knows Vampires are not real, so it is harmless way to indulge in a "I which someone would take me away from this" fantasy? Is it because unwanted/unplanned pregnancy isn't a worry with a Vampire Lover? Is it an insidious plot to keep women addicted to fiction where they are subservient to men and there by keep that as the correct state things in women's subconscious? Is it just a fad that will pass? I've heard all that discussed at various chat-rooms and Con panels, and I'm still not sure why Vampire Romance is so hot.