I think what he is saying is that it is easier to do something ad hoc in Monarch since it is a global service with unified storage and retrieval. A Googler can join the data of Gmail and Ads easily if they want, whereas combining the borgmon data of those services is either not possible or it involves downloading CSVs and performing the join externally.

> Does it allow different aggregation methods (avg/sum/max/whatever) for different metrics, like Carbon does?

All of these methods are available[1]. Stackdriver Monitioring is the public face of Monarch.

1: https://cloud.google.com/monitoring/api/ref_v3/rest/v3/proje...