It baffles me how some people can deny how great the Surface 3 is. The reason I have a Macbook Air 2013 is because it was absolutely the best device on the market at the time I purchased it. Nothing could compare to its amazing battery life, and flawless balance of CPU performance to GPU. However if I was faced between the 2014 Macbook Air and the Surface 3, it would have been a no brainer.
The MBA is an absolutely gorgeous machine, but the Surface 3 is the new kid in the block. Gorgeous resolution, great performance, good size and weight (the Surface 2 was chunky), and fantastic form factor.
I don't think there are many people willing to say that the three extra hours the MBA gets on a charge is better than having a 3:2 aspect ratio and much higher pixel density.
Considering that performance and price is roughly the same, the Surface 3 has a clear edge on hardware while having to work with such a daring form factor.
Hardware wise the Surface 3 is the best thing on the market right now. Some people have a problem with Windows 8's interface, but the system is extremely stable. Mavericks on the other hand, has a great interface and usability but it lacks the stability of Windows (I never thought I would say this). I consider the two OSs capable, but each needs to improve tremendously before I can say which one is better.