Well it's depends on your use .
I'm using moto x play now.
But i have seen features of Moto g4 plus .
All the features of moto g4 plus and moto x play are same.
Moto g4 plus come with some new features like fingerprint lock, better camera experience ,turbo charger.
Moto G5s is a better overall choice right now in terms of camera performance.
Moto X Play comes with a better 21mp Primary camera as compared to 16 MP in Moto G5s.Moto X play offers a really good camera performance as you can click crisper and clearer pictures in both outdoor and indoor conditions.
Though the front camera configuration is same on both the devices,
But for a better selfie experience, Moto G5s is a better choice as it comes with a front LED flash that helps the users to take a better selfie in low light and night condition.
You can check the camera samples at the following link Moto X play camera samples.