I played with the iPad Pro today... loved it.  It really felt like I was using my own pen, I didn't have much range because the thing was tethered to the table but I managed to do a rather intricate drawing of the mall interior through the window and I couldn't have done it better if I had done it on paper and ink.  Although instead of just leaving it, I showed it to some of the people that worked there and they loved it, and wanted to save it... of course, the demo version of the app doesn't let you do that, so we wound up accidentally deleting it immediately.

But I later tried an app on the Surface Pro... ugh, it barely responded to the touch of the pen on the screen.