I got my (mid-2012) rMBP about the same time as a friend got the equivalent MBP. I had to order mine with 16GB of RAM but he ordered his laptop with 8GB of RAM

I got my (mid-2012) rMBP about the same time as a friend got the equivalent MBP. I had to order mine with 16GB of RAM but he ordered his laptop with 8GB of RAM and installed a much cheaper 8GB to reach 16GB. There are a few things that it's nice to "fiddle with". Being able to swap out the SSD is another convenience.