I think both machines are excellent. But honestly, seriously, the resolution of the retina display is
really really really worth having IMHO, unless of course you only run your laptops in clamshell mode. I am working daily on it, analysing data and coding in Matlab, writing in Scrivener, using Lightroom (fuzzy but liveable with until the update), Illustrator CS6 and Pixelmator. Most of all it is the text rendering, it really makes a difference.
If you seriously work with photos, honestly the IPS panel, contrast and the amazing pixel rendering of photos at x1 makes the rMBP essential.
Anyone that has even a slight passing interest in typography, would be crazy to get a cMBP. Glyph rendering is sensational, you can pick out the detail in glyphs across fonts utterly invisible with the classic DPI.
The rMBP is an utterly solid machine and usable
today[1], and although I think
a lot of Apple marketing is finest manure of the bovine kind, the retina display
is magical and revolutionary and all the other market-spiel adjectives in spades.
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[1] I really don't get reticence for the first generation of the rMBP after having used it for two weeks for extensive work. The exception is if all you do is in Microsoft Office, not a problem for me as I can do 90% of my writing outside that junk and only import for final collaborative formatting. Some people hack their Office to get clear text rendering:
https://forums.macrumors.com/threads/1418567/