Entourage Calender vs. iCal

I posted this question in the Leopard Mail and Address Book forum but it occurs to me it is probably better suited here. I apologize up front for the double post.

My wife and I both have Macs (she a G4 iBook and me a G5 iMac). We both recently upgraded to Leopard We both currently use Entourage vs. Apple Mail and iCal mainly because she has a lot of corporate communication with people who are on Exchange and Outlook. We also send invites between us to help keep our schedules in order. When we first got the Macs and tried iCal and Mail there was an issue sending appointments and having them appear as calendar invites in Outlook. They just came across as emails about a meeting but the recipient could not "accept" or "decline" by using the buttons in Outlook.

I've read some articles that talks about how Mail and iCal are improved in Leopard. My questions is, has anyone had any experience using Apple Mail and iCal with people on Exchange and Outlook? I am interested in trying Mail and iCal but want/need to stay in sync with my wife's calendar invites, etc.

Any insight would be appreciated.

Thanks,
David