Planning on picking up the 128GB SSD/8GB RAM option with the black type cover. IMO 4GB is just not enough when you are talking running full desktop-class apps. Chrome, which I prefer over Edge, is a RAM hog. I'm not an artist and I have terrible handwriting so the pen is of no use to me, I never bought one for my iPP. The new mouse might come in handy though. I'll be taking it out of S mode as soon as I get it. I might even pay the $50 to put 10 Pro on it. I like the cross between extreme mobility and desktop class apps. I'll put a copy of Office 365 on it and some other apps I use. Great for on the go. I don't need LTE, I'll just use the hotspot on my iPhone. I think it will certainly take away from iPad Pro sales.
I don't really have any upfront concerns about it other than maybe battery life, but that will have to wait and see.