Is Google Cloud Datastore or Google BigQuery better suited for analytical queries?
As far as I can tell there is no support for Datastore in Pandas. This might affect your decision.
Currently we are uploading the data retrieved from vendor APIs into Google Datastore. Wanted to know what is the best approach with data storage and querying the data. 
I will be need to query millions of rows of data and will be extracting custom engineered features from the data. So wondering whether I should load the data into BigQuery directly and query it for faster processing or store it in Datastore and then move it to BigQuery for querying?. I will be using pandas for performing statistics on stored data.