The keyboard is definitely better on the yoga and it's backlit which is great, but the yoga is thicker and heavier than a surface, lower screen resolution (still 1080p IPS though), no stylus, no SSD (although adding an SSD is cheap and easy).
I'll personally be buying a surface pro 4 whenever it's announced (hopefully October 6th), but if you plan on typing a lot the Yoga is probably better and it's half the price.
Basically, if you primarily want a laptop that you can use as a tablet on the couch the yoga is great. I really need the stylus though, because of all of the math in my classes, so I'll be getting the surface pro for taking notes.
