NoSQL, I always understand it as Not Only SQL. At our place we use MongoDB (Main store), SQL, Big Query, Redis, ElasticSearch, then we also store data in S3 that we don't want to query or have the cost of storing in the DB.

Pick the right DB for your requirements. Management of them isn't that hard as they're hosted solutions, we've only got to deal with the cost of when a version is EOL, so upgrades or when certain queries will no longer work.