Yes, still using it for storing relatively unstructured blobs of JSON which I only lookup via key but update with various operators ($addToSet, $set, $incr). Also using it as a persistent session store and lately for storing rate-limiting information. I've come to like the MongoDB update operators and features such as the Change Events. However I will eventually be moving off MongoDB as I need horizontal scaling via shards, and the sharding setup of MongoDB is needlessly complex and brittle. Currently planning to go with ScyllaDB for my large-volume key-value blob datastore and some flavour of SQL for low-volume things which need more complex query behavior (user database, subscriptions). ScyllaDB will present challenges since I still want to have the ability to update single keys in big JSON blobs, even if my only lookup is by key.

If MongoDB came up with a better sharding experience where every box is equal and you don't need the dance with shards on top of replica sets plus mongos plus config servers plus arbiters I might consider it again.