Newbie here so not sure I'm worthy to post . . . but here goes anyway. Got a late-2012 rMBP a month or so ago with the lowly 128GB ssd. Been looking for upgrade options. I found this "mSATA SSD to MacBook Pro Retina" adapter on ebay: http://www.ebay.com/itm/261633884564?_trksid=p2060778.m1438.l2649&ssPageName=STRK:MEBIDX:IT Got a smokin' deal on Amazon a few days ago on the Crucial M550 mSATA 512GB drive, $169.99 plus tax. Installed the mSATA on the adapter a few hours ago. Fits fine and seems to be working great. To make sure TRIM is enabled, I installed Cindori's free Trim Enabler app. So for a little more $200 I've upgraded to 512GB! It's a perfect fit and BlackMagic's disk speed test is indicating that it's faster than the stock ssd.