I think setting the bar at 6.5 is a little high, depending on your squicks and reading style. Mine is 5.5 though I dont filter, just choose.
I just read 'Need a Little Company', a fanfic first posting by HeatandChills.
https://storiesonline.net/s/12801:i
It's based on the 2002 scareflick: 'Cabin Fever'
http://www.imdb.com/title/tt0303816/
I enjoyed it a lot despite I dont generally like fanfic and I dont care too much for heavily flawed lead characters.
A summary, to some, MIGHT be 'Self Centered Manipulative Bitches need Loving too.' I would be more sympathetic.
- And of course the male protagonist, having otherwise good intentions, really doesnt like her at all but she is one fine piece of ass, and he's drawn into her web.
The attraction of the story itself is the honesty of the author in the character depiction. She treats the personalities as well as the relationship between the survivors realistically. In the end, you're left to draw your own conclusions as to how it turns out.
I would bet she has a considerable number of under 5 rates.
I gave her a 9, solely for believability, combined with readability.
The explicit sex wasnt really all that much a turn on as it would have been if it were a typical romantic stroker.
Without saying so, she points out the 'urge to breed' invoked by an apocalyptic experience.
Your view may vary on it.