It's pretty and all . . but it looks like a Mac OSX shell.
I'm all for having options for my shell . . but I guess I want better options . . not just a clone option.
Is it faster?
Is it easier?
Does it have more features?
Is it skinnable?

The "Feature" page is pretty light on details.

The history is interesting:
Cairo was originally created by Michael Ciarlo as a simple Samurize
project containing a floating taskbar and hovering ’start’ menu. After
a few weeks of work Michael abandoned the project; it had no future as
a Samurize shell replacement and was limited by the program's abilities.
A few weeks after development ended on the Samurize shell, Joseph
LaFountain contacted Michael and offered to help develop the project in
a different format: Desktop X. Accepting the offer, the two began
working on concepts for the new Cairo shell. Once the project shifted
away from the original floating taskbar and start menu concepts, both
developers knew that Desktop X would not be an appropriate development
platform. Days later, concept work began for a shell written in C#.
Cairo was on its way to revolutionizing the Windows desktop.
Also very cool that our own PurrBall is a dev over there (according to the forums).