it also depends on how and more importantly, why, it is written and who is reading it.
a well written sex scene that verges on too graphic for some, may yet trump a more subtle sex scene that is poorly written, even a reader who prefers a more subtle sex scene may vote for the more graphic scene simply because it is better written, the quality of the writing is key for me, perhaps moreso than the subject at times.
for example if the scene starts "Delores felt excitement as her slender fingers ran through Carlos' thick wavy hair....." well i've put it down already, unless i need a laugh.
but if it starts
"this was wrong, all three of them knew it was dangerous, everything they knew told them it was a point of no return, but somehow the memo never got through to their organs and the chemicals in their bloodstreams didn't seem to care a single iota...."
i might read on a little further..