This brings up an interesting set of choices...one that I recently made. Not between these two but may in the near future. The 13" rMBP is 1699.00
the 15 " is 2199.00. To me the whole idea of a "laptop" is performance yes, but portability is key. a 15" "laptop" is kind of an oxymoron a fine machine for sure, but is it very portable ??? not to me.
Now lets look at what else you can buy for about the same do re mi.
I just picked a NEW 2011 11" for 699.00 it is great, small. super portable and fits perfectly, limited yes, but thats ok, now I and anybody here can buy a 2011
I Mac 21.5" for 979.00 apple refurb, 1 yr warranty too, free ship....SO....
for LESS $$ than one 13"rMPB one can get 2 very capable computers, one for heavier stuff at home, one to cruise on the couch or go on the fly.
Or for a small amount more, still the 2011 11" Air and the NEW I mac, again 2 great machines. That gets my money every time, yes not really the latest and greatest, although the 2nd option does get you that, but I think a whole lot better value. Hey the retina is nice, but it will come down in price....quickly....remember the 2008 Air.....1799.00 and they sell for what now....when you are 1st on the block, you pay, and thats ok, just not for me.
I'll wait...and it won't take long.