title: HBase cassandra couchdb mongodb..any fundamental difference?
body: <p>I just wanted to know if there is a fundamental difference between hbase, cassandra, couchdb and monogodb ? In other words, are they all competing in the exact same market and trying to solve the exact same problems. Or they fit best in different scenarios?</p>
  
  <p>All this comes to the question, what should I chose when. Matter of taste?</p>
  
  <p>Thanks, </p>
  
  <p>Federico </p>