SDL DXA and the content mashup
Consider using SDL DXA and its Tridion Docs Mashup Module to do your content mashup for you. SDL DXA and the Module already do a lot of the work for you.
RWS strongly recommends that you use the SDL DXA products and its Tridion Docs Mashup Module to set up a content mashup implementation. DXA comes with a number of Tridion Sites Components, Schemas, Templates and other sample resources already set up for you. You can customize these resources to fit your specific content mashup requirements. The Module also includes two different content mashup implementations for you to choose from.
In short, using SDL DXA as the basis for your content mashup is fast and easy. Only implement a content mashup without using DXA if you have very specific implementation requirements, which DXA and the Tridion Docs Mashup Module cannot satisfy.