The ability to scale horizontally with minimal effort as well as having built-in support for Cassandra natively - no need to use something like Fluent or Tinkerpop! The product has been developed by experts who have worked extensively with Apache Hadoop ecosystem and know how to architect solutions using those technologies. It's worth noting that there hasn't been much activity at Datastax these days. They've mostly focused their efforts on Cassandra 3.0 which was released last year. If you're looking to build out your own scalable cluster then this would be one of the best options available. I used DSE mainly because it supports all versions of Cassandra from 1 through 4 (DSE only supports up until version 2).