Biggest difference is RethinkDB is a JSON document store, and Cassandra is column-oriented. Cassandra is eventually-consistent, and RethinkDB is immediately con

Biggest difference is RethinkDB is a JSON document store, and Cassandra is column-oriented. Cassandra is eventually-consistent, and RethinkDB is immediately consistent with all writes going through a primary node for each table. RethinkDB also has a query language that's integrated very deeply with the driver language itself, vs CQL which is a SQL-like text string.