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It's pretty easy to install OSX on a laptop with the exact same specifications as the MacBook Air.

You have CLEARLY never gone the hackintosh route, have you? I have, a few times. And no matter if all the internal components are compatible, there are ALWAYS bugs popping out constantly: computer wouldnt wake up from hybernation, webcam without audio, volume stuck at max level, trackpad's multi-finger motions not working, etc.

If you wanna go OSX in any sort of reliable way, Apple is the only way.
 
It's simple. Ultrabooks are simply four-year-old technology that everyone else is trying to catch up on and trying to come up with the "next big thing". The reason why people by Macs is for OSX. Plain and simple, they won't settle for less just because of a spec update that Apple could catch up on as early as next week.

This reminds me of when my sister bought her first iPod... considered a Zune instead. Guess which headstrong competitor lost in the end?
 
There is no competition if the OS you're looking to use is OS X. The only "ultrabook" in this category is the MacBook Air.

If you're looking at Windows, then I don't see why you would need to get the MacBook Air, especially if there are other machines that appeal to you.
 
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