For databases comparison, I really like Kristof Kovacs page: <a href="http:&#x2F;&#x2F;kkovacs.eu&#x2F;cassandra-vs-mongodb-vs-couchdb-vs-redis" rel="nofollow">http:&#x2F;&#x2F;kkovacs.eu&#x2F;cassandra-vs-mongodb-vs-couchdb-vs-redis</a>