Black. I always go back and forth on colors with each release because I get tired of the previous color. My iPad Air is white - my iPad Pro will be black.
Silver. I had an iPad Air which was silver and white. Not really keen on space grey. Though if they did one with a silver back and black front. I might have gone for that.
I ordered a silver by mistake. It was too early and I clicked the wrong button. Will be returning it for a black one IF I decide to keep it. And that's a big IF right now. The thing is too heavy to use comfortably in bed. I'm spoiled by my Air 2. Need to see if it grows on me over the next 14 days.
I was going to get silver, but I ended up going with Space Gray because of the black bezel on the front.
My car is black, my watch is black, and I wanted it to match. : )