I guess I'm in the vocal minority, I would recommend spending the $100 for the CTO upgrade with Apple and get the 500GB 7200. The main reason is Apple will fully support it. With a 3rd party drive, when it fails Apple will send you on your merry way to the 3rd party manufacturer for a replacement. Secondly, I've seen multiple threads here on MR (the place where many people profess to be such experts, 🙄) end up stripping screws or scratching the the bottom plate from the inside while trying to do the upgrade. To each his own, but for only $100 I would pay it Apple and let them install an Apple supported HDD.