It works, so long as you're using Exchange Server 2007. Compared to Entourage, it adds some features and lacks others.
As always, Mail and iCal are faster than Entourage. Their interfaces are less cluttered. iCal will show conference rooms and other resources properly, not as contacts like Entourage does. iCal will display multiple Exchange calendars overlaid in the same window; Entourage requires separate windows that each cover whole screen, so it's difficult to compare calendars. Mail supports hyperlinks in messages; Entourage doesn't. Mail's spam filter works better than Entourage's did.
On the other hand, Entourage supports Exchange categories, and can theoretically sync notes and tasks to the Exchange server. (Doesn't work for me.) iCal doesn't support this. Also, Entourage has Projects (which will never sync to Exchange) and supports links between messages and/or events, which are nice.
There's really no reason not to use Mail/iCal/Address Book if you have Snow Leopard and use Exchange. Since everything is stored on the server anyway, you can use Apple's applications and Entourage at the same time, and go back and forth if you need a particular feature. I use Mail and iCal most of the time now, but I haven't gotten rid of Entourage, either.
Neither supports server side rules, and neither is as capable as Outlook.
I have no doubt that Apple will add better Exchange support in future versions of OS X, and Microsoft has already promised a Mac version of Outlook in the next release of Office.
Unfortunately Apple is not completely honest about the "out of the box support for Exchange". Here is a good
read.
There is nothing dishonest about what Apple has said, in that article or anywhere else. Apple never said it was producing a Windows Outlook clone. And that article is over a year old, long before Snow Leopard came out, so he was just speculating and several of his points are inaccurate.
