Ok I installed Zimbra. Here are my comments.
Though the interface looks really nice and tidy, these guys cannot think it seems that some of us are not mouse users! I hate having to use my mouse to navigate around!!! It takes way too long!
I want to be only tabbing around. In outlook, i can just do as following: never have to touch the mouse:

ctrl-n (for new task)
this is a test task tab
1d (that`s to schedule a task for tomorrow, what a novel idea!)
alt-g (to go straight to the categories)
per (to scroll down to my category called personnal)
ctrl-enter to save

That`s so simple! Why is it nowadays we are forced to use our mice that much? We don`t even have the time now to breathe, yet alone fool around with computers. Make it simple people!!! please!

Ok, I will try thunderbird now.
Too bad evolution doesn`t work in windows because from what I remember, it was pretty simple on this app.