Just ordered a MBP retina w/ 256 SSD. I heard 256GB SSD comes in 2 flavors: Samsung and Sandisk, which has a lower write speed than Samsung. How likely is it that I'm going to end up getting a Sandisk SSD? And is the speed noticeably slower? //Edit: If I do get the Sandisk one, can I replace the SSD to Samsung later on and get the faster speed?