The new MacBook Air is great, but be sure to verify what SSD disk you got when you purchased it. Otherwise you might have been given an old and much slower Toshiba disk instead of the Samsung disk that is/was? supposed to be shipped with the new Air.
So why does this matter? Well, simply put, make sure to get what you're paying good money for. And you will actually notice the speed difference if you compare the two disks to each other, even with simple tasks such as unzipping a fairly large zip file.
Apple hasn't acknowledge this in public, as usual. But they will give you a new unit if you ask. If you, like me, bought it from a retailer, you might have a hard time swapping it, but you should still be given an option to return it due to it not delivering what's promised. That's what I did.
How to verify that you have the correct disk in you're machine then?
Open up "About this Mac" -> "More Info" -> "System Report" -> "Hardware" -> "Serial-ATA": Check the Model field, if it starts with a TS you've got the slower Toshiba drive.
Check out this video for more info:
It's important that you bring this up, otherwise, Apple and others might think it's OK to fool customers on hardware due to people not "caring". At least I don't want that to be the norm. Make a statement, make some noise!