I was a long time MS Outlook user, not only for email, but for synchronizing with my Palm, where I started with a Palm m100, then cIII and now a Zire 71. I tried StarOffice, and this other one I forgot the name. I was not happy.
My Outlook crashed twice within a week. All emails were still saved, in a separate file, but all my message filter rules were erased. And from the looks of it, My data might be erased completely soon if another crash may occur.
So I decided maybe it is time to switch to Thunderbird for my email. And even if Mozilla made the Calendar Project and Sunbird, they are not yet synchronizable with a PDA. So for other PDA Sync functions, I’ll use the standard Palm Desktop and for emails, Thunderbird. Fast running, stable, happy.