Had the same situation,, got the rMBP 13" i7 512

fantastic laptop i should have done it after the Feb refresh. reasons made me do it now
1- i can't change all my home device from Wifi "n" to 'ac' in the short term,, so not benefit from the ac bump plus ac wont see light in public hotspot before at least 18 months (you can stream HD on n)
2- there is no performance gain between IB and Haswell.
3- i dont game, so the HD4000 is fine for me.
4- portable, light, 7 hours, and just need it now!!
that was my argument, and in any case its a 2 to 3 years cycle, Brodwell with 14nm architecture is a game changer, we can see quad-core in a 13" ,, but this is 2015