I just picked up a surface book recently and it works flawlessly. I used to have a 15 inch macbook pro retina which I also enjoyed (got stolen... that's another story though), but the surface book is obviously far superior for any free hand drawing or note taking due to the touch screen and stylus, and also has superior display to retina both in terms of resolution and color accuracy. I would recommend it as slightly better than the macbook pro retina, and far better than the surface pro (if you can afford the price difference) due to its superior functioning as a laptop, larger screen, and faster hardware. Essentially the surface book is a laptop first with secondary functionality as a tablet, whereas the surface pro is a tablet first with secondary functionality as a laptop. Seeing as ~85% of the time a laptop is the form I use it in, I prefer the 2-in-1 that maximizes the laptop experience primarily.
I would take it with a grain of salt when you see some reviews that say surface book (and i would assume similarly for surface pro 4) are unreliable/unstable. I'm sure some of these people have indeed received defective products, but I can safely say that a lot of the "complaints" are simply a case of people who are not tech savvy people trying to use a non-apple product, which rarely ends well. These products are not quite as user friendly as the Macs and do not function flawlessly out of the box. Mine crashed and the track pad glitched several times within the first couple hours of use and I became very skeptical as to the viability of the product after having read numerous reviews that seemed to foreshadow such problems occurring. I presume this is where a lot of the negative reviews are coming from, and people just give up and return the product because they don't know any better. However, after updating the firmware and Windows 10 OS to most recent versions it has worked flawlessly ever since (going on 2 weeks now) and couldn't be happier. Other users have echoed the sentiment that simply updating to most recent firmware and OS will fix the vast majority of glitches and crashes some people are experiencing.
I would say the surface book is probably the only Windows laptop that is superior to the macbook in hardware build quality, performance, and functionality. Most PC laptops feel cheaply built, have an inferior display to the macbook retina, and the trackpads are complete garbage which is why I had previously preferred the macbook, but the surface book is imo the first real exception to that rule in virtually every respect.
Would definitely recommend surface book to anyone looking for a solid productivity laptop/ 2 in 1 unless you are just completely partial towards apple product synergies with your phone/ipad etc, or a completely non-tech savvy person who will be overwhelmed by the slightly less user friendly, albeit more functional, windows 10 OS