I think you'd be hard pressed to run Win8 on a 32Gb drive with 4Gb Ram (although, admittedly, my Surface Pro runs Win8 adequately on 4Gb so it's the tiny drive that will get you).
If you compare the base 1299(wifi) Pixel to a 1299MBA(13") they look about equal as far as I can see.
The Pixel gives you a higher resolution display (2560x1700 vs 1440x900) and a slight bump in processor speed (i5/1.8Ghz vs i5/1.3GHz). The MBA also has an intel HD Graphics 5000 vs the Pixel's HD 4000.
The drawback to the Pixel imo is that there is no 8GB ram option and it's stuck with a 32 GB drive (even if it is an SSD). Also, the MBA has a longer battery life (8h vs 5h) and USB3 ports instead of USB2.
It's actually the battery life that pushes me towards the MBA. I picked up an XPS13 "Sputnik" in an effort to move away from Apple hardware and was immediately disappointed with the battery life. The Pixel doesn't appear to be any stronger on this front.
