I have to admit, the Surface Book with its detachable hi res large screen is certainly going to make people think hard about it when pitched against the iPad Pro, especially if they aren't already part of the Apple ecosystem.
I had been planning to buy the iPad Pro myself, along with a Pencil, and replace my Lenovo Yoga 13 sometime later, but I'm seriously going to have to reconsider now. It's not that I'd be abandoning Apple (I've made far too big an investment in my kit to do that) but that the Surface Book would cover a lot of bases that would have otherwise required me to buy two separate products.
Well played, Microsoft. Very well played.
The problem with the SP Book is that once you pull the screen off the keyboard, you loose the power of the GPU. So it's a compromise - either needing to be a laptop, with decent specs, or a tablet with ok specs. It is not going to be both. And drawing on a laptop screen is about as challenging of a thing to do as you can get, unless you have herculean strength to hold you hand up in the air AND maintain fine motor skills necessary to draw on-screen.
I think Apple recognized that the iPad Pro was going to become a Wacom competitor, more than a touch-screen laptop sort of thing. Just seeing how they market it tells me Apple recognizes the difficulty in using a touch screen laptop, while Microsoft pretends that it's no issue (while mostly showing people how they use their devices with keyboards connected...