i have macbook and this weekend i tried surface pro 4 and surf book...sorry to say but for me my macbook pro 15" and my 12" macbook when i have a little work (besides wifi browsing) at over 50% cpu use, my macbook last for 6h and 23 min
on surface pro 4 for same task, also at 99% battery ramaining after 5 min the battery last for 4h and 40 min
So for battery stand point if you what something else than only wifi web browsing you have a down side
Now closing apps without keyboard and trackpad is very difficult and not so cool experience to touch to close the apps with your finger. Using 2 apps in the same time, has UI lag, i think around 24 fps, macbook does not in el capitan unless i have more than 3 tabs opened and working excel and importing
it is more difficult to use surface pro AS an laptop with that keyboard in a plane or on your lap, almost anywhere beside a desk or hard material.
The material does not come close still to the macbooks feel...macbooks feel like metal and sruface book and pro feels like hard plastic
if you go surface pro 4 with i5 or i7 (i tested the i5) when you do some medium work to hard work the vents start to be heard and blows the air and you feel it on your right hand while you using as a tablet
So still a hybrid CAN'T be perfect as a tablet or CAN't be perfect as a laptop from build quality to UI
Now i have to say that these devices are the best windows OEM devices of all time. But still being objective you feel the Apple ADN when they design their macs, and the attention to everything, i really mean everything....
i can't even use a port from surface while charging..it is masked by the charger....