Here's a quick an easy way to deploy both Mongo and Postgres, and start comparing them:

    git clone http://github.com/shykes/sqlwars
    cd sqlwars
    pip install dotcloud
    dotcloud create sqlwars
    dotcloud push sqlwars
    
    # Open mongo shell
    dotcloud run sqlwars.mongo mongo

    # Open postgres shell
    dotcloud run sqlwars.postgres psql

Happy hacking!