Well, thank you; however, my concern was not that of a laptop vs. a tablet, but rather the “value” of the added cost for the Surface Book. Although one may wish to quibble with the logistics of the designs, in general, these two devices serve the same general purpose; that being a laptop with tablet functionality.
In the event someone else happens along this thread in the future, I will give you my take on the research I did; again, assuming identical base hardware inside.
The Surface Book is larger than the Surface Pro 4, about an inch. So, if screen real estate is important to you, this may play a factor. This also allows the Book’s keyboard to be slightly larger than the Pro 4’s; so, if you have larger hands, the Book may be more user friendly.
The Book has an option for a dGPU, this is a Graphic Processing Unit. If you are planning heavy graphics use (i.e. Art, 3D drawing, CAD, etc.) or gaming, this could be beneficial. Although if you’re really seeking a heavy gaming unit, you may wish to look elsewhere.
The Book has a 12 hour battery life compared to the Pro 4 at 9. However; the Book has a battery in the keyboard as well as the screen (tablet). So, if you’re using it in tablet mode, you may not experience the full 12 hours.
The Book has 2 USB 3.0 ports vs. the Pro 4 at 1. The Book will support a full SD Card where the Pro 4 will only support Micro SD Cards. An important note is that the SD Slot on the Book is located in the Keyboard portion of the device; hence, you loose the expansion in Tablet Mode.
If you like to use your laptop in your lap (i.e. LAP top), the Book will work much better in this configuration vs. the Pro 4 due to the “kick stand” which doesn’t work quite as well.
Finally, when converting the Surface Pro 4 from laptop to tablet mode you either quickly pull off the keyboard, or wrap it around the back. The Surface Book requires you to “unlock” the tablet first; this is not instantaneous. In a world where we complain about every extra click it takes us to get to the final page, this second or two of “unlocking” the tablet, seems an eternity.
Good Luck!