well, I owned 3 MBP 15" , 207, late 2009 and late 2011 (actually I'm selling the last one...) and I just bought the MBP 13": there is a relevant difference in portability.You've already got the 15" MacBook Pro. There is no functional difference in portability between the 15" MBP and 13" MBP so you are spending money to buy a redundant machine. The only computer I would be considering for your usage is the Retina MacBook.
Sure, the rMB is even better.