Biters aren't really that hard to deal with, most of the time it's just a lack of socializing, she might not have been very well handled or handled very often. It's not as bad with girl rats, I find their bites don't tend to be quite as strong, lol.
It's a patience game, when I got my Luciela she was so terrified of humans she wouldn't come out of hiding til she was sure I'd left the room. If I sneezed or coughed, she'd hit the roof. She still squeaks when I pick her up, but at least I CAN pick her up now (and that is with a few months of working with her, considering she wouldn't even come near me at first, she's come a long way). You just have to be careful about how you handle them and make sure to handle them every day and they'll eventually get used to it. Jorats made some very good points. Imagine how you'd feel if a giant hand came down on you all of a sudden ;p You just have to be patient, it's a wonderful waiting game. As long as you have the time to spend socializing her, I don't see why you couldn't take her on! Heck, the previous owner might just be unsure about rats and might be exaggerating, when you get her you might find she's no problem at all!
She really is a gorgeous girl, I am so jealous ;3;