Interesting.
My thought was that I can read well-written stories anywhere (sci-fi, fantasy, mysteries, even humor), but good stroke fiction is very hard (oops!) to find, so my reviews almost always are based on the jerk-off quotient primarily, with the quality of the writing (style, grammer, spelling, punctuation) being a modifier to that base number.
A notable exception to that general rule was Harold's recent story about the frog in the frying pan, to which I gave a very high rating with the caveat that it probably should have been posted to a different site.
Hmm.