I've spent the past week transitioning from an iMac to a Macbook Pro High Retina. I'm blown away at how fast and powerful this thing is. I was a little worried about the move but it's so much better than the desktop I was using.
The screen is truly amazing, and thank you Google for having Chrome Canary available. Standard resolution software does look a bit blurry and having all my extensions and bookmarks rocking in high retina on Chrome Canary is a godsend. The old iMac looks blurry to me now - and I used to be wowed by the screen on it. The grass is always greener and in amazing definition I guess.
The most impressive thing to me is: the weight. I've used a 15" Macbook Pro some over the past couple of years, just not as my "main" machine and the difference in the weight is a significant pleasure to me. Just carrying it in one hand up a flight of stairs feels ... right. I'm sure if I ever got an Air I'd love it but the combo of lightweight, power, speed, and the jaw dropping resolution has made me one happy camper.