Although I have used Macintoshes professionally since System 6, I by choice use Windows computers since Windows 7 - working in enterprises means that I need to use Windows apps, and I don't need cross-platform-aggro. Having said that, I have a 2013 MacBook Air and a 2013 MacMini (with an aftermarket SSD and aftermarket 8 GB RAM - the Mini is unusable if you don't do this).
Even on Yosemite I don’t really like the Finder. It's ok, and I can live with it, but as an operating system shell it has a few faults. Windows 7 does too (don't mention Windows 8 or 8.1 - but the Windows 10 technical preview might one day be as ok as Windows 7).
So, I have a MacBook Air 13" mid 2013 model. I really, really like it. It's, given the present state of the art, the best laptop out there for my use case.
I don't use Boot Camp. I boot into OS X 10.10, but have Parallels 10, so I can use Foxit Phantom PDF Standard and Microsoft Office 2010 (2013 really annoys me). I use Foxit because OS X Preview bloats file sizes badly, and Foxit has a bunch of other abilities.
The battery life of the Air is a standout. I can easily take it out for a full day's work of 8-10 hours without worrying about the battery. As of November 2014 I can see that battery life is waning by maybe 10-20%, so a refurb will definitely be required at the 2 year mark.
The screen is very nice, the size of the whole machine is just right for a portable computer, and the weight is great for a machine of this power and battery life. The power brick isn't huge, it has Intel 5000 graphics and a backlit keyboard. Time Machine works well to back up the whole disk including the Parallels files. WiFi is reliable and works on 2.4 and 5 GHz. Recharging is surprisingly fast. The speakers are fine for watching YouTube or listening to internet radio in a hotel room.
An AUD$20 DisplayPort to DVI cable means I can use a second screen with just about any monitor. It also works fine with my 27" Thunderbolt Display and a DisplayPort to HDMI adapter - all very easy to use.
Some foibles of OS X annoy me, but they aren't the MacBook Air's fault. I really like Chrome shortcuts on the desktop in Windows, which aren't available on OS X.
I won't bore you with comments about everything about the MacBook Air mid 2013 - it's a laptop that has all the things that come along with laptops.
My conclusion - after 16 months with the MacBook Air mid 2013? It's the best laptop I've used or owned.
(c) 2014 Andrew Calvin, Sydney Australia