Both are good devices in the budget of around 8k, while Redmi 4x is an expected device with promising specifications, Though it is difficult to compare but as per the expected specs Redmi 4x should be better as it has the following advantages:
It should be comparatively cheaper than Redmi 4, It should be priced around 7K while redmi 4A is priced around 9A.
Rest of the specifications are similar, but as redmi 4X is not released yet, we need to wait till the device is available for the actual review and comparison.
As per the expected specs Mi4 Prime should be better ,It looks stylish, features IR blaster and has a strong configuration for handling day to day task easily. The gaming performance and the camera quality are excellent.Lenovo K6 Power 32GB vs Xiaomi Redmi 4 Prime
In terms of battery performance both the devices are similar, Both the devices has 4100,Ah battery, but overall redmi note 4 should be better with better processor, better RAM,better screen resolution and better storage. Redmi note 4 vs redmi 4
In my opinion you should go for Xiaomi Redmi 4 ,It is a all round powerful device, this is the probably the best option for you.It is offering great featured smartphones at a highly affordable price tag. Xiaomi Redmi 5A vs Xiaomi Redmi 4 16GB