I have been wanting this for months, but I must say I am disappointed, not in the product but in the price.
The default configurations have small "hard drives" and no i7 processors. If you BTO in an i7 and a larger drive, then it literally costs just as much as the 15-inch model, in spite of having a smaller screen and no Nvidia discrete graphics card. So unless you have unlimited money and extremely limited desk space, it's hard for me to figure out why you would buy this rather than just getting the 15-inch.
The higher model should come with an i7 for no additional charge, and the 512 GB drive BTO upgrade should be cheaper. It currently costs about $500! The difference in price between a 256 GB SSD and a 512 GB SSD is certainly not $500, and while it's conceivable that the proprietary components in a Retina MacBook would be somewhat more expensive than a standard SSD, I think $500 is just too much.