Well lets talk about the motherboard since the i5-7500 and AMD 1500X are so close to each other in performance. If you're aiming for a system that is updatable over the next few years then the AMD system makes the most sense as you'll be able to reuse all the components when you go to replace the CPU, AMD has mentioned in the past that the current AM4 motherboards will be usable for the next several years, at least until 2020.
So when Zen+ comes out it should work in todays AM4 motherboards.
If you go with Intel and an H270 motherboard you will almost certainly need a new motherboard when its time to update.
As for gaming the i5-7500 and 1500X trade blows with the i5-7500 winning most of the games. The 1500X is not very far behind...