FWIW, I've got a 15" Retina that I bought when they came out. Its NEVER had a single issue and its my daily use and travel computer. Its always on and only gets powered down when I'm on my way to the airport.
I use nearly every version of mac that comes out in my work including the new "VaderPod". Wish I could have kept it.
My issue is that he wants new price for old hardware that many may not understand can not be upgraded. (Yes owc does sell SSD's for that model).
He does admit the "potential" ram issue but brush's if off and does not state that it can not be easily replaced. Many will assume pull a simm put in a new one
not "replace/exchange the main board".
The speed difference between ivy bridge and haswell retinae is significant. I know, I have used multiple version's of both types.