I posted my problems with it as a response to a sibling comment. Since this was four or five years ago now, maybe all of this has been fixed, but that's not something I'm going to depend on in production any time soon.
Also, the MongoDB users you list must be taken with a grain of salt. For example, you list Facebook on that page. Nope. The description is "...adapted the storage engine API, extending MongoDB into new workloads and new capabilities." That is, Facebook acquired Parse, which used Mongo. Facebook ported MongoDB to run on RocksDB. Facebook shut down Parse. End of MongoDB at Facebook. You list Google, and the mouseover is basically that you can run MongoDB on GCE. I'm not saying that Mongo is unusual in this behavior. It's how most people listing "who uses X" build their lists.
Also, the MongoDB users you list must be taken with a grain of salt. For example, you list Facebook on that page. Nope. The description is "...adapted the storage engine API, extending MongoDB into new workloads and new capabilities." That is, Facebook acquired Parse, which used Mongo. Facebook ported MongoDB to run on RocksDB. Facebook shut down Parse. End of MongoDB at Facebook. You list Google, and the mouseover is basically that you can run MongoDB on GCE. I'm not saying that Mongo is unusual in this behavior. It's how most people listing "who uses X" build their lists.