The MongoDB ODBC driver has been gaining a lot of traction as MongoDB gains traction.  This driver gives you ODBC and SQL access to your data in MongoDB.  I know of specific cases where it is currently being used in production with Excel and Tableau as well as Informatica.  A lot has been written about the MongoDB ODBC driver.  A few good posts to read are:

1. “How to do reporting with MongoDB using ODBC” – in this post, Domantas Jovaišas explains how to setup the driver and how to connect from Microsoft Excel.
2. “Simba Technologies is bringing the power of SQL to Cassandra, Hadoop, BigQuery, and MongoDB” – in this post, Jonathan Allen interviews Simba CTO George Chow who explains “The driver currently exposes complex document constituents (e.g., array or nested document) as a JSON-encoded VARCHAR. We are planning to decompose these into additional denormalized columns.”  George then goes on to explain some of the roadmap.
3. “MongoDB ODBC Quickstart” – this document explains how to set up MongoDB on Windows, set up the ODBC driver, and connect from both Excel and Tableau.
4. “Informatica PowerExhange for MongoDB” – this video is a good example of how you can set up and use Informatica PowerExchange to connect to MongoDB using the ODBC driver. Note that the Informatica connectivity with MongoDB is read and write so you can move data both ways.

The above are all very good to help you get up and going with MongoDB and using ODBC and SQL to get at your data.  MongoDB is a solid database engine and having an ODBC driver for MongoDB which also incorporates SQL brings everything together very well.