While thunderbird itself works great with Zimbra in general, it is VERY close to be a viable alternative to Outlook with the Lightning Addon.

I'm asking for support from the Zimbra community to get more votes for this enhancement request for Lightning (which benefits Zimbra directly, and thats why I'm asking here):

https://bugzilla.mozilla.org/show_bug.cgi?id=482984

Basically, because Zimbra has different calendar shares for the TASKS and the CALENDARS, I'm hoping that someone can add the ability for the lightning addon to use seperate default calendar for both the Tasks and The Calendars, and optionally the ability to hide different calendars from different views (TASKS tab/Calendar Tab).

Right now it clutters things up in Lightning when you have your Tasks calendar visibile in calendar view and your calendar share visible with the tasks view. Things get worse when you have many different calendars.