The Surface Pro is a brilliant machine, techwise, and Windows 10 is not bad at all. But the problem for me personally is that, unlike OSX and iOS, Windows does not scale very well. You can "enlarge" certain features and menus of apps, but many do not play well with that and end up having text so tiny you can't even read it.
For example, one Windows app I use is Starry Night Pro Plus. But on a 2800 x 1800 screen, or whatever the Pro 4 is, the app's details on things like planets and stars, when you hover over it with the mouse, are so tiny it unusable. A high resolution on a small screen that that, with no scaling, is a terrible experience. But the Mac version of Starry Night Pro, even on my 15 inch Retina Macbook, is perfect. With OSX, I like that your screen size can be any resolution, and it always looks the same in terms of text and image sizes.
Now, if you could get OSX running on a Surface Pro. . .