People seem to really gloss over the size and weight issue. It only barely enters the specs/price discussion, but it makes a huge difference to how it feels to interact with the device.
I've had my new rMB for 1 day so far. I'm working from my apartment, and walking from room to room with the rMB in one hand, using it with the other hand, without a second thought. It's approaching the size and weight of an iPad, but with all the capabilities of OS X. Sure, it's not as fast as a MBA or MBP in the most advanced functions, but it's capable, in the literal sense of the word. I've been using Safari, Skype, Spotify, my NAS admin app, and a VNC app simultaneously with no trouble. I edited some photos and videos from a recent trip with a totally acceptable amount of processing time. Sure, I could do things "faster" with a rMBP, but would I trade this thinness, lightness, and real-world portability for it? No, not after today...
I haven't had a chance to travel with this laptop yet, having just received it, but I'm so looking forward to it. My point is that, even just for home and local use, the ease with which you can carry this from the sofa to the kitchen to the bedroom has been enough to change how I view using a full computer.
In contrast, my 15" MBP (Late 2008) now sits in a Henge Dock, connected to my ethernet switch, my NAS, and my home entertainment center, never to be lugged anywhere again! My wife (web developer) uses a 15" Dell laptop for work, and she couldn't believe the rMB--like, almost couldn't really believe that it was a computer, and not just a cardboard mockup.
I'm tempted to say, you can't put a price on this level of real-world tactile usage. Except that Apple did: $1299 and up. Worth it? For me, definitely. I feel like I got what I paid for: an ultra thin, ultra light OS X computer that I can literally take everywhere--at home and away. What's so hard to see about that?