Not even a question. Get one while you are in NYC.
Most people are complaining about the screen on the MBA and raving about the battery life. The two are completely correlated. Yes, the new rMBP will see improved battery life, but not by a huge amount, maybe 20% at the most.
The processor speed bump is marginal 10-15% and the graphics performance will see a similar improvement.
So what, you will be one generation behind. But that is only one year. Use the savings to upgrade a year sooner next time, in 2016 rather than 2017. unless you believe that the computers double in value each year, i think you have already justified this to yourself...
I've bought a rMBP and I hope I've made the right decision.
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What was your last laptop? ( gradz on your new machine! )
My last laptop was a 15.6-inch Sager NP5160, with a Core i7-2720QM 2.2 GHz, 8 GB RAM, HD 540 GB (which I replaced for a 240 GB SSD) and an NViDIA GT540M video card. I bought it in early 2011.
Pretty good configuration, but that's it. Bad keyboard, terrible trackpad, unusable webcam, heats a lot, heavy and cumbersome, plastic-feeling. And it's currently not working (it's the third time it stops working without a reason, and now I must take it to support again).