The Pixel has:
Better processor (i7 2.6Ghz vs i5 2.7Ghz)
Slightly better resolution (2560×1700 vs 2560x1600)
Double the RAM (16GB vs 8GB)
The Macbook has:
Double the SSD storage (128 GB vs 64 GB)
Better integrated GPU (Iris Pro 6100 vs HD5500)
So I would say there is no clear-cut winner.
Regardless what people thinks, the base specs for the Pros are quite fair for the price.
EDIT: I was forgetting that the Pixel has a touchscreen display, somehting that Apple doesn't offer at all, at the moment.
Cpuboss gives the edge to the i7, but if you have some source with benchmarks comparing the two CPUs (or similar ones) I would be really interested in seeing them, in particular how TDP affects performance.
In my opinion the recently refreshed 13´Macbook Pro is one of the most interesting machines on the market, for the price.
Dell and Google have a better record on this front, and the XPS 13 and the new pixel are "solid gear".