I pre ordered this for my new Macbook Air 13" as a friend of mine who bought a cheaper case for hers ended up not being able to use some of the ports etc.
I've had it for just over a week and whilst the case fits beautifully, it has scratched more quickly than I thought it would. The underside is quite badly scratched, perhaps where it's been on a table with crumbs or something - I can't think how else it could have happened as I've been quite careful with it. There is one small scratch on the top.
At the end of the day though, it is plastic (shiny plastic) and it is there to stop my Macbook getting scratched, so I guess in that sense it is ding it's job fantastically! Other than that, no complaints - nobody is going to be looking at the bottom of it anyway!
It arrived the day after dispatch - on a Sunday no less!