You had me until the "like Cassandra" bit ;) If there's one thing where Cassandra loses the battle with other NoSQL tech then cluster managements is probably it

You had me until the "like Cassandra" bit ;) If there's one thing where Cassandra loses the battle with other NoSQL tech then cluster managements is probably it. Also, it's a bit unfair to compare RDBMSs with Cassandra. Clustering is inherently going to be more complicated for RDBMSs. Incidentally it's actually where I feel MongoDB deserves a bit of credit.