It seems to be a pretty common senario; people thinking X new technology that Y large site used will solve all of their problems magically. Comparing MongoDB to

It seems to be a pretty common senario; people thinking X new technology that Y large site used will solve all of their problems magically. Comparing MongoDB to others; it's similar with Redis and from experience less so with Cassandra (probably the steeper barrier to entry) / Riak (lack of commonality with a standard DB is way more obvious) / Hbase, etc...