It's nice, very nice even, don't get me wrong. I'm enjoying mine, but honestly speaking the screen is not as impressive as some people make out.
First off, colour accuracy and black accuracy wise, it's still a good degree off some other screens. Especially before calibration. The Sony Vaio Z (top end model) for example, seems to have a much better screen in this regard, as do some of the business models of certain laptops.
Second, despite being retina, certain images, even higher res one's, sometimes look less sharp on my Retina than on my old 17" MBP.
Lastly, the size. Beautiful screen, but the retina aspect doesn't really make much of a tangible difference. In all honesty I'd have just preferred a slimmer and lighter 17" Macbook Pro, even without the retina.