AR Comparison:
This link is by an engineer walking around CES looking at the AR display technology being touted by various Original Equipment Manufacturers. As such it's a good primer on the state of the art. The problem they are all trying to solve is to overlay an image over the 'real world' - and current tech either reduces the amount of light that reaches your eyes or else introduces sone colour distortion.
https://www.kguttag.com/2018/01/15/ces-2018-part-1-ar-overview/