Exactly. I also migrated companies off from MongoDB after a total data-loss that even the vendor could not recover or explain.

Postgres is surprisingly capable, rock solid service that is always my first choice. I also used Riak in production for several years and the biggest problem was with it that the operations team forgot the root password because they did not need to login for a long time. :) I have heard great things about Percona XtraDB but I never used it. RocksDB is also interesting but it is just a data store not a full fledged service, based on it there is one service called TiDB that I have heard is very reliable.