OK, so let's talk about this little machine. I come at it from a different perspective from most people - I don't have electricity in my home, and I haven't had a home desktop computer for more than a year. So this is very much my main computer, and for my use its ability to work away from mains electricity is significant. So I can confirm you get about three and a half hours on battery - less if you plug in an external drive - which is, frankly, not quite as much as I'd hooped. Obviously there are a lot of things you can tune to improve economy, and I'm still experimenting there. It's also not quite as quiet as I'd hoped. Don't get me wrong, by PC standards it is pretty quiet, but you can hear the fan. No part of the machine gets more than mildly warm, though.
For the rest? Well, it may not quite look a million dollars, but it looks amazingly good for eight hundrd pounds. It's a beautifully crafted piece of kit. The case looks extremely sharp and designer - yes, I know that it's a very sincere flattery of the Apple 11 inch MacBook Air (Dual-Core i5,1.6GHz,2GB,64GB Flash,HD Graphics), but frankly it's none the worse for that. The screen seems extremely sharp and bright; the keyboard, despite its very short travel, is positive and pleasant to type on.
Obviously, as I'm using Linux, I can't comment on the problems Windows users are having with the touch pad. Multi-touch drivers for the touch pad are apparently in bleeding edge kernels already but I'm using 3.0 which doesn't have multi-touch. But as a single-touch touchpad, it's very good. And the machine feels blazingly fast, booting from cold in under ten seconds, and snapping large applications like Netbeans and Eclipse open.
Linux? Oh, yes, it installed very straightforwardly. Almost everything worked out of the box. The significant thing that didn't is sleep mode - you need to set up a sleep/wake script in /etc/pm/sleep.d, but fortunately there's documentation on how to do this out there on the Web...
Which brings to the matter of Windows. I haven't wiped it off yet, but Windows - by itself, with no user data or applications - occupies more than half of the total 128Gb SSD. By contrast, Linux, with a full graphical desktop, two software development environments, several games, a full office suite, three browsers and all my music fits into 9.7Gb of the 40Gb I've partitioned off for it. I'm not - yet - pushed for space, but sacrificing more than half my total storage for an operating system that's only any use for playing games seems a waste.
In the long term, both the SSD and the screwed-in battery are slight liabilities; both will, in the long term, need to be replaced. But, brutally honestly, we don't keep laptops in the long term. I bought this one because the SSD in my three year old Dell Mini 9 has died. I could have replaced just the SSD, but I didn't.
In summary, the Zenbook is exceptionally elegant and desirable; nice to work with, well made, light and portable, and seems likely to be durable. In terms of bang for your buck, it isn't bad, but you are paying for the fancy aluminium case and you would probably get better graphics performance for the same price if you bought a standard plastic laptop. You'd also most likely get more storage, but I do appreciate the dramatic speed of the SSD. There are also machines that you can buy for the same money which have more battery life. But there are few machines which are more elegant. If you want MacOS, then by all means buy a MacBook Air; but putting any other OS onto a MacBook Air is significantly less easy than putting it onto a PC, so if you don't want MacOS then the Zenbook - with almost identical specification - is a better buy.
Edited to add - if you're going to use Linux, I standby my opinion this is a very nice machine. But if you want to run Windows, don't buy it. Under Windows neither the WiFi nor Bluetooth work (they work out of the box under Linux) and you can't download update to the Windows drivers without clicking to 'agree' to a legal document which takes away all your consumer rights.