Andre,

For example:
1. How do i only display tasks with category names starting with "Home:" in Evolution???

2. How do i group tasks or journal(memo) entires as shown on the picture below in Evolution???

There are many others(text formatting/field presentation) and they are all things that matter to me more than the OS choice.

Don't forget that view customization in Outlook is the same across Mail/Tasks/Appointments/Notes/Journal.
Also, i'm not just putting down linux alternatives - every other alternative linux or not(MS Entourage doesn't count) claims that it can do stuff but doesn't even come close!!!
But it's so simple to get equal....