First, I want to state that I have a ton of respect for what Microsoft is doing. This is the Microsoft I've been waiting to see for over a decade.
That said, here's the truth. Just a week ago I tried out a Surface Book, and within the first few minutes I could immediately tell it was not as polished as a MacBook Pro.
The first thing that stood out is that the screen suffered from a considerable amount of ghosting. It looked great as long as I wasn't actually doing anything. Dragging a window around or even just moving the cursor though revealed clear visual defects.
I also immediately noticed that the trackpad, while high quality physically, struggled with gestures involving multiple fingers. Maybe this is configurable through software, but I just didn't find the trackpad's recognition of gestures to be nearly as good as that of a MacBook Pro.
On the same topic of gestures, doing a four-finger horizontal swipe in Windows 10 to switch between virtual desktops resulted in a very visually jarring animation. The experience just isn't polished like it is in macOS. This surprised me because I use Windows 10 extensively on my home desktop and generally find it very polished, but that's all using a normal mouse, not a trackpad with gestures.
Next I noticed that the laptop's screen was physically wobbling. I suspect this is because the screen is so much heavier than normal due to its unique detachable design. But I found this quite annoying. It was apparent that even just typing on the laptop with it on my actual lap would lead to screen wobble.
All this popped up within minutes before I even tried out any of the laptop's unique features. The version I was looking at had a price tag of $2800. At this price range, I think Microsoft still has work to do. None of this is to say it's a bad product. I was just expecting a bit more from something with such a premium price.