Have used a MBP since early 2011 and love it (it was my first time coming over to the Apple computing side). I am at a point where I want to repurpose mine and pick up a new rMBP. I have the standard 8gb RAM 500gb 15" model from then and am looking at the $1999 model now (15")....obviously, the flash storage is different but will the overall speed of the system be noticeable? I'd like to just walk into the store and pick it up vs. having to special order one. Thanks.