[coolsunglasses]

Honestly, just google "HBase vs. Cassandra" and go from there.

Just keep in mind that between the two, Cassandra has improved a lot more than HBase has.

HBase can be an easy choice if you already have a Hadoop cluster and want to roll the results of Map-Reduce jobs into HBase keys.

The DataStax crew has a decent stack for turning batch/OLAP jobs into queryable keys.

If you have no need of that, want tunable consistency, favor write availability over read performance, then Cassandra might be a fit.

Just uh, don't pretend Cassandra clusters are necessarily trivial to manage just because they're homogenous.

IMHO: put off moving to any of these technologies as long as possible.