This is a tough one. I have the 2014 15" and I bought the 2016" 15 (after initially buying the new 13" and exchanging it). I bought the 2016 13" thinking I would have two machines, but when I saw the new 15" I thought it would make more sense to trade up for that and sell my older 15".
After three days with the 15", it didn't seem to make sense. It was beautiful--the screen was slightly nicer, I liked the narrower bezels, the slight reduction in weight, and I appreciated the touch bar and touch ID. But I couldn't get used to the keyboard.
So, I've had the original 12" rMB from 2015, and briefly the non-touchbar 2016 and the new 15" and I simply couldn't become accustomed to the keyboard. It felt too stiff, too rigid, and generally not satisfying.
It got me thinking that at the end of the day, what am I really gaining by purchasing the newer device? A slightly lighter computer with a slightly nicer screen--but not huge in either case--and the touch bar, which is neat but by no means essential. For me, the same can be said of touch ID. Losing ports, mag-safe, and a much more usable keyboard didn't seem worth the trade-off, even with the roughly $1,500 Canadian I was likely to get for my 2014... I was delighted to get a refund this aft of 3k Can.
Now back on my 2014 and I'm more than content. But in your case, given that you haven't already shelled out for either, I would suggest buying new--if you prefer the keyboard. It's no small matter. It makes for a very different experience.
I gather you've tried it in the store and like it?