This can be used as a drop-in replacement. It disk format is compatible with leveldb. But once you upgrade to RocksDB, you won't be able to switch back to Leveldb (unless you restore ur data from a backup).
One definite use-case for RocksDB is a message queue that has a high number of puts/gets/deletes.
Also, please look at options.h to determine what options to tune. A not-tuned system will not show you much perf difference from leveldb.
Thank you. My company uses ApolloMQ but in a relatively low-data setting. (10-15 queues, with less than 5000 messages in a queue at a time) I don't know that it would make it worth it to move to a different data store but the idea was fascinating to me so I was curious. Thanks for the response.