I remember last year that was all the talk, but its died down. I guess people feel Screen out weighs the Self Maintenance. Same with cars, they don't want you in there so you have to buy the computer for diags. Im in the market but I swear I just can't decide. I like the fact that I can get a 2.7 add my own memory and what ever SSD and have a smokin machine. But the fan may be to loud. And then there is the Haswell beast on the horizon and maybe a new feature I would want. anx
In a way it has. The OP did just want the advantages of the cMBPs over other MacBooks, so I offered what I have

Im one of those who would go, and has gone, to rMBP. My rationale behind it is: Because of the retina screen potential IR problem and the greater price range, I would feel more comfortable with Applecare for my device, therefore any RAM issues would get me a replacement/refurbished Macbook (which can be good if they are out of stock of your exact model and could give a newer model - such as the early 2013 for the late 2012). An SSD issue would be no problem to replace under applecare or the warranty.
But the most likely of reasons I went with the rMBP despite lack of self-upgrdability was that I have discovered how much the Macbook line depreciates (or doesnt depreciate to be more exact) over the years. Right now I feel a bit uncomfortable that I went the way of the 8GB RAM instead of the 16GB, but if I feel the need to upgrade, I will wait for the refresh of the rMBP, sell my current one, and buy the newer model with my desired specs. Its my way of thinking "instead of keeping my rMBP for long term and possibly paying several hundreds of dollars on repairs/warranty, I could just sell my rMBP, and spend that several hundred on the difference for newer model".
I also moved toward the rMBP for several other reasons. For the 15" I love the form factor, it is SO THIN! (its entire thickness is as thin as the thickest part of the macbook air) + there is less of a black border around the screen on the retina + last but not least, NO SLEEP LIGHT! I never turn my computer off, and at night my cMBP's sleep light would slowly fade on and off. Its pretty bright and gets really annoying having to put something over your laptop every night. To me that was one of the most unexpected practical improvements Apple has done for the rMBP line.