Lightness is a big factor in my interest in the product. The 4GB RAM CTO option makes it more useful. However, my enthusiasm is tamped down by the slow USB connection and lack of keyboard backlighting.
It's not for everyone but it's a nice refinement of the MacBook Air's elegant minimalism.
My hope for the future: USB 3.0 support and the return of backlit keyboard.
As a college student, the weight(or lack of it) is a huge plus. I had gotten to carrying my iPad and when I would use my 15'm MBP, I could feel a big different.
But even more then that is the tiny screen, making it so easy to fit in a bag.