Unfortunately, there is not one ideal database. Things to think about when selecting a database(s):
While news aggregators search thousands of sources, they do not include all sources.
Nexis Uni offers limited metadata. When you run a search, click on one of the delivery icons, you will see one of your options is to export Metadata to an Excel spreadsheet. You are able to export the headline, publication, summary, and date. One may not add or delete a category. You may deliver up to 1000 results simultaneously.
The other databases do not appear to offer downloading the metadata. Databases see their metadata is proprietary and usually do not want to share it.
Finding historical circulation and web traffic data is much harder. Some have luck using a search engine, like [2006 and newspaper circulation]. The following resources may be useful: