people seem to forget humans are vicious savage territorial creatures, if we can get away with it we will, i don't believe anyone that says 'why would i kill someone?' as some succint excuse to remain the moral one... we are animals, we have instincts to mark, claim, and kill to protect that claim... someone, an 'other' that is completely identical to us that believes they ARE us as much as i do... violence and primal instinctive urges are inevitable... many a philosopher has pretty much already stated the natural state of humans is wanting to kill each other simply because anyone besides 'me', as in the conscious 'me' that i am now, will at some point try to control me, therefore to prevent that, i must kill them... this clone-issue is just an extension of that, i cannot control them that is me, therefore to ensure my life is mine, i must kill them...

as someone that is married, as you seem actually interested in people taking this seriously with actual value put in, yes, there is a difference... children and spouses go back to that 'claim' bit of our instinct, if someone else, another me or not, tries to claim my husband... that's reason enough for me to brutally end them... in fact it is my connection to him that i value more then most things in life that preserving it would be reason enough for me to kill in the first place... this 'other' would know and think this too, thus a bloody war between us is on the horizon... how this plays out and how it ends would further define us as separate beings, one the victor, one the scorned... this would likely cause a lot of animosity and result in further conflict until one of us is dead or submits... more then likely dead...