Over the years I have seen a move to a more temporal view of AGGREGATES. As an advocate of functional programming, I prefer this approach, but I think seeing this as an “X is better than Y” proposition is naive. Rather, having these as tools in the toolbox is a far more pragmatic approach when it comes to designing, developing, and maintaining software systems. - Devon Burriss. 

Explore some of the flavours that an AGGREGATE could take and walk through some of the reasons why you may want to pick a specific flavour.