Bench-marketing aside, I guess nobody ever expected MongoDB to outperform Couchbase. It's strengths are elsewhere, like the query language, secondary indexes and document model.
That may be true, but they both have document models and Couchbase Server will have a complete query language based on SQL, secondary indexes, and support for joins.
Precisely, but as of today the document model is limited (at least in comparison to Mongo). I'm following these developments for a while and I agree that they'll be killer!
Is the report comparing 9 active couchbase nodes v 3 active mongodb nodes? Am I missing something here?
It compares 9 nodes of Couchbase Server to 9 nodes of MongoDB. Couchbase Server reads and writes to every node, but MongoDB only reads and writes to primary nodes. That's the problem with active/passive topologies. MongoDB can read from secondary nodes but only if a) you don't require strong consistency or b) you don't mind degrading write performance - it would have to replicate to all secondaries nodes before the write finishes.