Originally Posted by climber
I used Entourage for years & liked it pretty well. I "upgraded to Outlook in Office 11 and thought that I couldn't get along without it... that's when I started having repeated database issues with Outlook! it reached the point about a month ago where I was getting errors and being forced to rebuild the database nearly every other day. in a fit of frustration, ask my wife how I was acting, I finally switched over to Apple Mail, Address Book and Calendar. it was a PITA for about a week, then it was easy. the nice thing is the easy integration with my iPhone 4s. I don't think I would go back. I still use Word and Excel extensively, so I really doubt I would change that.
Totally agree with regard to using Outlook without Exchange. Pain in the &$$.
Jules is however talking about using Outlook with MS Exchange. Totally different way of working than 'using Outlook' which as you point out does not (easily or particularly well) interface with the iPhone (for example). Exchange is the 'glue' that keeps your email on a server (user owned or third party service). For those that don't want to manage mail servers I fully recommend 123together.com.
For example I run two Windows machines (laptop and desktop) with Office, an iPhone and Mac Pro w/Office. Mail, calender, etc. is always in sync with all devices. With Exchange you have all of the services you find in any 'real' office environment including backups, calendar sharing, etc.