Hi,
I had a Early 2011 MacBook Pro 15" Antiglare model (w/ apple care) with 8+ repairs (including 2 motherboard repairs, 1 screen replacement and numerous of little things).
I called the Apple Care customer line and explained the situation. They told me then whenever the next thing occured, they would consider giving me a new model (mid 2012). *The MacBook Pro was in repair at the time*.
When I picked the MBP up from repair, it had this scratch at the bottom located near of the screws (slipped technician). I showed my disappointed at the Apple Store and that did it. They decided to swap the unit with an mid 2012 antiglare model.
So, with Apple Care and many many repairs, there actually is a big chance you can get a new model. They just don't offer it themselves.
(I sold the new unit and bought a retina model

).
They even swapped my 256GB Crucial M4 SSD onto the new model. It was a easy sale with it's specs.
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Make sure you tell them that you rely on the machine for work or if your a student, that you need it really bad. You've spent such a amount of money on a machine which happened to be so unreliable. Tell them you are the last person to make a big argue out of things but that this even get you a little bit disappointed and agitated.
But stay polite. That'll do it every time.
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I always make sure I get Apple Care with my machines and I have managed ( of course with the failure of my machines) to get the unit swapped within it's Apple care period. I have honestly not spend a penny more on any new machine since the MacBook Pro I bought in 2006. Sold the new unit every time for a different model of whatever.