I bought a 2011 13" mb pro online and planned on purchasing an aftermarket ssd...which I thought would be just like replacing a regular hard drive. It turns out the choices are more difficult than that, so I wanted to post the results of my research in case it helps out someone else. The difficulties come from 2 different areas: Performance Degradation Firmware Incompatibilities Some drives experience performance degradation over time once you've filled up the drive, primarily because osx does not support the trim command and many drives rely on that to solve the problem. The newest osx that ships with the 2011 macbooks (and the lion beta) enables trim support, but only for apple oem drives. Some people are hopeful they will do it for other drives, but I think it's a very real possibility they won't. Some drives also experience a number of other problems, typically related to sleep and hibernation, long pauses, and basic install problems. Manufacturers try to solve these with firmware updates. I eventually concluded there were 3 main types of drives I could get: Sandforce Controller Intel X25-M Apple OEM The sandforce category includes the ocz vertex 2 and the owc mercury extreme. These drives don't have the performance degradation problem because their firmware adequately handles it on its own, but they do have firmware problems. Not everyone seems to experience problems, but I read complaints from users of every sandforce drive I looked at (even the owc which seems to be the best in this regard). The Intel X25-M is very reliable from what I read, with hardly any complaints from users. However it does suffer from performance degradation over time, meaning it will slow down quite a bit after it runs out of free space. For my purposes, I didn't like either of these options. I wanted a drive that was guaranteed to work and wouldn't degrade over time. That pretty much left only the official apple drive. I then contacted various places and tried to buy one of these...the only place I found that would sell one said it would cost $900 for a 128gb! Someone else suggested I check ebay and that's where I ended up buying a drive. They are frequently listed as toshiba drives in the title and are typically pulled from other macbooks. I spent way too much time researching all that, so I figured I should at least document my thought process a bit.