I've got a 13" one here, about 10 days old. The machine is the best laptop I've ever used, and I've had a lot of them.
I expected a dog of a machine with laggy scrolling, screen and heat problems etc. and have been completely surprised at how well this thing runs. It does have a slight image retention issue when I run the test pattern but you really can't notice it.
It runs Call of Duty as well as the 2013 Air I have sitting next to it and stays cooler running it as well. If you are interested in the machine I'd say go for it. I don't notice anything laggy about it..in fact opening finder windows etc are faster on this than on the new Air. I have no idea why.