I love the size, ports, magnetic power cable, kickstand, touchscreen and pen, the convertibility to a tablet, and the fact the Microsoft and Adobe apps (main things I need) run so well on Windows.
I missed the superior Mac trackpad (more and better gesture support in Adobe), the familiarity and comfort of the OS, and the instant-on of OSX. Also the battery life is better on the MacBook Pro. Also, I now have to run Malwarebytes to keep malware at bay. Never worried about that on the Mac. Also, I miss airdrop and iMessage (I have an iPhone and iPad).
It was a frustrating weeks-long transition to Windows because I had to retrain my muscle memory, find replacement utilities (like Seer to replace the inbuilt Mac Preview), and I had to get used to new ways of doing some basic things. But now, I prefer the Surface and rarely use my MacBook.
At this point, I have grown so fond of the Surface form factor and touch screen that I won’t consider another Mac unless Apple offers something similar. OSX isn’t enough of a draw anymore to tolerate hardware problems.