I believe that Zen is only from their servers. But they have all the bells and whistles that you would ever need. You'll have to pay $25 to $60 per agent per month for all those features.
If all you want is a knowlege base and to have a spot for members to create and mange messages back and forth with support, hesk does that really well.
We added it a couple of years ago because emails were not getting thru for a large number of our members, now they can login to the helpdesk and check a support ticket to see if we have taken care of the issue. No more dealing with lost emails
Yeah!
T.