Dremio is focused on a combination of data access, acceleration and a self-service analyst experience (Tableau/Qlik one-click integration, data curation and data management).

We also invest heavily in our pushdowns. For example, we invested heavily in our Elasticsearch capabilities (support for CONTAINS and Lucene syntax, Painless and Groovy pushdowns, index leveraging, etc) and I'm pretty comfortable saying we're the best in world at exposing Elastic in a SQL context. Similarly for our other sources (join & window pushdowns in Oracle, SqlServer, etc, high speed predicate application in Hadoop, Mongo aggregation pipeline pushdowns including support unwind, etc).

I don't know Querona well (just a cursory site review). They seem much more focused on classic federation. It would also be important to understand when they repackage the Spark source connectors versus where they have built something that pushes down more powerfully (which you typically need for the best performance with these newer data source systems).