The university where I work doing computer support is almost finished migrating to Zimbra. I find it hard to sell people on using the web client because I feel like I'd be lying to people if I said it was great or even good. The best I can manage is "it is OK, but a bit buggy."
I typically wouldn't use a product that was so buggy--I feel like an alpha tester. I've personally encountered dozens of bugs and issues (and, except for a couple of cases, they have been in the course of trying to use Zimbra rather than trying to find bugs).
It's not my job to log bugs in bugzilla, so I haven't logged any of the ones that aren't already there. Nevertheless, I wonder why Zimbra is so buggy?
1) Are the programmers lousy?
2) Is any QA testing done?
3) Are new features more important than a solid base product?
Let me choose issue that I think falls into each category.
1) The advanced query language has a "size:" keyword. The help says "Specifies messages whose total size, including attachments, is a specified number of bytes, kilobytes, or megabytes." Now I don't see any use for "size:1111b" but since that's its job, it should work. It doesn't. If I use "size:>1110 size:<1112" on my account I get a bunch of records, but "size:1111b" returns none.
2) The help says you can tag items by dragging them to the tag. Except if you happen to be using the calendar month view. The month view mysteriously doesn't allow dragging of items. Sorry, I said 1, but here's another similar one: The help page "Assigning Tags to messages and other items" says "Select all the items to be tagged using Control-Click or Shift-Click." This doesn't work with calendar items.
3) I find the calendar so useless, that I'm forced to use the Outlook Connector, but I'll pick a different issue.... I've used lots of desktop and web e-mail clients and can't remember another message list view where every column isn't sortable. Hence, while I personally would never have implemented any column sorting unless all column sorting would be implemented, obviously other priorities prevented this from occurring with Zimbra. (The advanced search feature does mitigate this issue somewhat; the lack of column sorting, though, effects the user experience.)