I was wondering if Zimbra Desktop was less server resource consuming than other alternatives like Outlook or even the Zimbra Web IU.

I think it is. Why? Cause it basically downloads the e-mail from the server but it's the user's computer the one that will handle the file to be viewed, moved, deleted, etc. Later the server will replicate this action with the message it has in its own storage but this will be done asynchronously.

This is another advantage: since most of the processes will be done asynchroanously the user won't need to wait until a delete, move, send operation is completed. Am I right?

Even using AJAX Web UI makes the user wait for doing a lot of processes like send o delete emails. In fact I'm pretty sure the interface uses more SJAX than AJAX. This is not bad but the user experience seems to be better using Zimbra Desktop than using any other mail client in combination with Zimbra CS.

What do you think?