Because Gabriel’s Inferno was once a Twilight fanfiction, I don’t think it’s a bad thing to compare the two of them.
One of the biggest changes that I found was the point of view. Twilight uses the first person present. We only get Bella’s opinions, thoughts, feelings. Everything else is filtered through her eyes. The POV has its faults, but in Twilight, it works reasonably well.
Inferno is going more for a third person omniscient. We hop from Julianne to Gabriel to Julianne to Paul to Gabriel to Julianne to Rachel and all over again. I’m not sure if this format worked. Half the time, I felt I was being hot-potatoed from one head to the other. Part of the time, I wondered if I really needed to see what Paul or Gabriel or Rachel were feeling in X situation. And part of the time, I found that “the inner voices” of the characters just weren’t different enough to distinguish.
You can see hints of the cast of Twilight in Inferno. Gabriel’s mood swings make him reminiscent of Edward; it’s obvious that Rachel is supposed to be Alice, Grace is Esme, and Rachel’s fiancé is Jasper. I’d lay money that Paul is supposed to be Jacob and Christa is supposed to be Rosalie. But while I can find some similarities between Bella and Julianne (liking to read, not being “hip”, having distant parents, being frugal, being clumsy), I hate to too closely compare them. Because (and I know I’ll get tons of sh!t for this) I think Julianne is more likeable. But I’ll get into that later.
Even the story itself is remarkably similar. Gabriel must “struggle” against his womanizing, promiscuous ways, lusting after a woman who is so pure and beyond his grasp. Sound a little like Edward, who must “struggle” against his vampiric desire to drink Bella’s blood, the most wonderful smell he’s ever inhaled?
Of course there are tons of things that are different. Edward was never Bella’s teacher; Bella was a teenager when her story happened; the events of Twilight occurred primarily in Forks, Washington, USA. But these are just details; if you were to change Inferno to Gabriel being a wealthy newspaper editor in New York City when Julianne was 35, the story would be nearly the exact same.