We have now been faced with three distinctly different versions of the android at this point, and each seems to be used for completely different purposes. Further, their potential lives outside of their function seem to be limited in different ways. First, we were shown Ash in Alien who seemed to be more like what you would think of as a typical robot. He could pass as a human physically but there always seemed to be something off about him throughout the movie. He seemed completely emotionless even in the face of danger. When his true purpose was revealed, he was also incapable of deviating from his given directions, no matter the cost to the crew. He had no real interest in anything outside of his programmed purpose and never questioned anything.
The androids in Blade Runner were nothing like Ash, however. They were pretty much indistinct from humans except for memories that could be created artificially and superhuman abilities that were unique to each design. Unlike Ash who never questioned order, it seems like all the replicants every did was ponder their own existence. While the world of Alien presents androids as beings completely distinct from humans, Blade Runner presents such humanized robots that it causes us to question what it means to be human when faced with them.
Finally, the androids in Ghost in the Shell reveal a representation of androids that is somewhere in between the other two. Though we haven't seen the whole movie yet and I can't be sure where it it going so far, the main android (I can't remember her name) seems to have some free will and strangely limited human emotions. She feels no shame about walking around naked, but yet also feels sympathy for the man that had been implanted with false memories. She is also very aware of her place in the world as an android and has not visibly questioned this yet. This is an odd blend of characteristics for an android and I'm interested to see what the purpose is.