I got an iPad Pro a few weeks ago. I was on the fence between it and a Surface Pro 4 for quite some time. It was the pencil in the end that won me over. More specifically, the noticeable lower latency and better ability of the Apple offering to do actual circles as opposed to Microsoft's solution.
The surface book doesn't sit very well with me. The specs aren't bad, but there were two things in particular that took it off my short list: 1. I don't like the gap between display and keyboard with it when it's closed. It seems like a huge waste of space to me in a backpack. 2. Cost is prohibitive to me.
I stopped seriously gaming on mobile devices years ago. I'm pretty picky when it comes to frame rates at higher quality. Something that desktop PCs will always excel at compared to a mobile device. So, I have a custom PC for that purpose. In fact, my next PC build is going to be a wall-mounted one, with liquid cooling. Something like this (still in design phase right now) but without the custom liquid cooling. I'm most likely going to go with an integrated system, like one of the Corsair Hydro series products:
http://www.overclock.net/t/1424387/gallery-build-log-ultimate-wall-mount-rig-maxxplanck-v2-completed
Complete with carbon fibre wrap. Maybe put some flame decals on it. Then some racing stripes. You know ... Stuff that will make it go really, really extra fast.
It's going to be legendary.