magu: In my case, a Retina 13" with 8GB RAM will be better. I can then upgrade the SSD later on.


MBP Retina has non standard components like MBA, so you won't be able to upgrade any internal components down the line. 

The SSD is replaceable, according to OWC.

Oh yep, you're correct, although it's still a non standard part so you will end up paying more compared to a regular 2.5" SSD I'm sure, better than nothing I suppose.