Fandom Sex Fic Meta Stuff

Okay, so there was some discussion happening on twitter, and it's become obvious pretty fast Twitter is not a medium to cope with these thoughts. So, I pose to you a question:

For any of you who have been in more than one fandom - what differences (if any) have you noticed in the fic sex? Tropes, kinks, styles of writing, common themes, ratings, recurring setups? Are there things that are more popular in specific fandoms? Things that are nearly impossible to come by? Are any fandoms kikier/freakier/slashier than others?

Is the way the sex written different in different fandoms? Eg. jenepel commented that Bandom tends towards dirty/faily sex while lorelaisquared mentioned that Gilmore Girls fandom tends toward more romantic sex.

Are there fandoms you got into particularly to read certain kinds of fic? Are those kinds of fics more prevalent in those fandoms? (Example, I started reading BBC Sherlock fic because I just wanted to read fic where John and Sherlock figure out they are IN LOVE already, and there seems to be PLENTY of that, so all the delicious PORN WITH FEELINGS for me).

What kinds of fic do you think are underrepresented in your fandom of choice? Or overrepresented? What types of fic are you so sick of reading and which ones could you read over and over? Which ones would you KILL to have more of?

Please discuss!