I'm about to bite the bullet on a high-end 13" rMBP soon (the late-2013 base rMBP that I won in a raffle is inadequate for my regular usage, which involves running VMs frequently). I'm maxing it out to i7 (I've got plenty of funds to afford the slight speed bump and the slightly larger cache) and also 16GB of RAM (for my usage with VMs). However, I've heard that some people who ordered the 256GB 13" rMBPs got the SSDs in two flavors: the slower SanDisk and the faster Samsung. I'd like to know whether the 512GB variants come in Samsung-only or not. Thank you.