RE: Sony Viao Z.
I actually just bought one of the z2 / 2011 models in the UK having had a Macbook Air stolen. The reason being I needed a faster computer for work than the Air, a better screen and the ability to run windows...and I had some Amazon UK vouchers to go with my insurance from the Air. PLUS, if Apple do release a retina display Mac I can afford then I have time to return the Vaio to Amazon.
In comparison to the 2011 Air though:
1. The Vaio is much faster, the combo of the full power i5 and the Raid SSD IS faster (and the SSD's have garbage collection).
2. The screen on the 2011 Z2 is MUCH better than the Air. I have the 1600x900 screen on the Vaio, but whilst still TN so not great viewing angles (though slightly better than the Air) the colour gamut is much better, so too contrast. And it's not as glossy.
3. In some ways the Vaio is not as well built; I have a tiny flaw on the wrist wrest (a pinprick size dot unpainted) and it has more flex overall...
But, I'm not as worried about dents as I was with the Air
4. The Vaio keyboard is fine, no better or worse than the Air (though the Vaio back-lighting is nicer)
5. The trackpad is worse than the Air, but fine for windows, actually it's good as windows ones go.
6. It runs as cool or cooler than the Air and has as good a battery life (this is with an i5 2410m).
7. It's made in Japan not China.
So, overall, if I was buying a laptop today (as I had to last week) and I wanted the best overall package and you could live with Windows, then the Vaio Z, 2012 OR 2011 is a better option.
But, as I said, I'm half expected a very nice new Macbook Pro upgrade so I will consider returning the Vaio IF Apple up the screen resolutions in their laptops. I want a Mac, but not with the current low res screens.