Well the Samsung PM830 is two things: fast and reliable.
As much as Apple wants to cut ties, it's hard to not use the PM830 now because of the price point you can get it for at the OEM level. It's last gen controller and last gen NAND.
I love my 768 that I have in my rMBP. I keep a spare area of about 75-80GB in order to allow the controller to wear the NAND evenly.