I'm on my second 2011 15' MBP 2.3Ghz. I already had one I bought last week replaced by Apple Store on Sunday. It would not wake from sleep (when it automatically went to sleep from Energy Saver preferences). Then the HDD volume was corrupted. Now my replacement MBP is not waking from sleep. I think there may be an issue with these models. I am off to the Apple Store again before this HDD volume corrupts.