[carr]

I think, that what a company produces reflects their standards.
I don't know much about user experience and bugs on the frontend, as don't use it. But for me programming Zimlets and changing skins means constant frustration.
Frustration because of a complete lack of good documentation.
Frustration because not one developer takes a look into the forums, answering questions, that would take them about 5 minutes, instead of a hole day for me browsing through code or trying to guess soap requests.
Frustration because I find HTML inside core JavaScript files instead of Template files.
Frustration because of inconsistent use of code or frontend elements (e.g. checkboxes).
Frustration because of poor HTML and CSS and no attempt to clean it up (e.g. tables everywhere!)
Frustration because a lot of dynamically created elements don't differ in CSS classes even though they are different (e.g. OK_BUTTON and CANCEL_BUTTON)
Frustration because even the support doesn't answer development questions... am I supposed to guess everything?

I do really really think, that the Zimbra frontend is a bad product. Yes it is hard to put in such functionality and keep sane. Yes it is hard to have clean code. But for ****s sake write a documentation or at least answer questions in the forums.
People would actually contribute if they would know how.
And please no more features. There are enough. Try to clean up your code... just once.