I cannot say for sure it will be for (or at) Christmas, but I'm pretty certain I'll purchase the Surface Pro 4 "soon" for work, school, and personal use. I had the pleasure of getting my hands on one at the Microsoft store, and I was quite impressed (just waiting for a sale, haha ).
Would be interested in hearing Linus' thoughts in a review for it. Where the outside/appearance is much the same, Microsoft made some major improvements to the keyboard and internals (correcting the thermal/throttling issues that Pro 3 had).