2015 ex demo vs 2017 MBP 15 inch UK

So i've been eyeing up a new 15inch MBP for a week or so and the best deal I have found is £2,149 with 2 years cover at John Lewis.

I went in today and they have an ex demo 2015 for £1,512. It has a slight scratch underneath but the keyboard and screen are as new and it also comes with 2 years cover.

Is the difference between these models worth the £600+ difference? Just looking to see if anyone has either/both.