I picked up a Surface 2 and purple type keyboard for £420, just £20 more than the iPad Air (16GB) so I'm pretty chuffed.
My use case is heavy Outlook usage for work, pretty high Office usage, note taking, decent remote desktop app, web browsing, music, video and Kindle. For me it's ideal and right now I have all the apps I need.
IE11 is a significant step above other tablet browsers, I just don't feel they compare. It's incredibly fast and great to navigate. Plus full flash is a great advantage as well.
I spend 80% of my time in the modern UI with the balance in Outlook and office. Office is surprisingly touch friendly as well. The keyboard just tops it off as well. The type keyboard is great, the touchpad is serviceable but when combined with the touch screen it's more than enough.
Battery life is great, I'm getting over 10 hours consistently. Easily making it through a working day plus a few hours at night chilling out on it.
I compared it to an iPad 4 today with Logitech keyboard and it seems lighter and a better combined unit. The Air shaves a ton of weight off which will make a significant difference. But if you want a laptop which can also offer productivity you just can't compete with a decent keyboard and Office. MS really are right, I don't care what people say. If you have any inkling that you want to be productive on a tablet then iWork on an iPad or Quick Office on an Android tablet just do not compare.
The hardware itself is beautiful Exceptionally well made. With the pair sat on my laptop the type keyboard seems a little noisy, a little hollow sounding. I'm a little worried about the VaporMg finish. It has a few marks on it already, not dinks or scuffs, just dirt maybe, or where a pencil has caught it and the lead is hard to clean up. Also the felt on the type keyboard will be pretty hard maintenance (I think).
Definitely recommended, I think I've turned a few at work who feel the iPad is too limiting. Full office and the USB port is really a big appeal. As well as integrating into the work environment in ways that the iPad just can't. I'm a big fan of the iPad and own a Mini but it's just not suited to a work environment, MS should really be selling this as a great BYOD device.