I never was into twilight, nor was I into 50 shades of grey, so I never even THOUGHT the two might combine in any way XD Now I know~~~
But yea, I do believe there is enough crappy fan fiction out there to give a bad name to anything that might be decent.
I thought it was interesting how be brought up all the star wars novels, since they are published works that people buy...yet they are technically fan fictions.