I've been a user of ZCS as well as ZD since august of last year.
I'd be lying if I said the transition from our old system of Exchange/Outlook had been easy for our users and I personally filed a number of bugs, mostly concerning usability.
However, since the opening for more devs have been posted, the amount of bugs squashed, mostly on the usability side, has been really stellar. Even the dreaded sort by to: issue has been started to get adressed even though there's work to be done on that one.
So I wanted to congratulate the dev team for their renewed commitment and I'm looking forward to the continuous improvement of this great piece of open source software.