I have tested previous versions of zimbra on distro's from Fedora to openSUSE. Zimbra has always been very impressive, so I keep watching to see how it evolves. I downloaded the 5-betas and 5.00 and 5.01, but didn't get round to installing. However, I've just installed to test 5.02 on ubuntu 7.10 gutsy (tweaked a couple of files in /etc) using the ubuntu6 installer.

I love the shared calendaring, shared mailboxes, jabber!
I haven't yet tried the briefcase feature, but have just downloaded the XPI for firefox.

I have tested web interface in Firefox2 and ZimbraDesktop in WinXP and Linux (kubuntu 7.10) . It's nice to have a Zimbra app that will look and behave the same regardless if I'm using Win/Lin/Mac
I have also tested Thunderbird with Lightning & Zindus extensions for shared calendaring via CalDav and synchronized GAL / local addressbooks.

Absolutely Fantastic.

I am also very glad that IM is working nicely now. I connected via Kopete chat client (Pidgin works too) and was also pleased to see ability to make floating buddy list and chats via web interface (I couldn't find IM in ZimbraDesktop though) .

Rave! absolutely fantastic product at any price! Thanks guys, and thanks too for paying such good attention to your forums and posters. It's nice to know one is being heard when a bug is filed or help is requested.

On a final note, I'm glad the MS purchase didn't (yet) happen.