My Sister's Keeper is unique on SoL, the convoluted plot keeps you hanging until the last paragraph.
Onagerian Surmise is a true craftsman, the dialogue is crisp and realistic, the characters multidimensional and disturbingly human. I say disturbingly, because in this particular story, the main protagonist, whilst not being as mad as a bag of squirrels, is definitely delusional.
If you're looking for sex, or a cheap thrill, My Sister's Keeper is not for you. If you're looking for a gripping short story that grabs you viscerally, and draws you into a strange, altered reality, you won't be disappointed.
Technically, Onagerian Surmise' only failing, in this story and others, is his failure to guard against silly homophones, writing 'peak' instead of 'peek' is one example. Other than the odd typo, a failing we all suffer, that's the only real criticism I have.
My Sister's Keeper is a disturbing and enthralling story.
Read, and enjoy!