Mike and The Geek, I would suggest that you do more than simply go to the Microsoft marketing site to find a justification for your decision. You have a hospital that saves peoples lives and they are looking to you for the best solution for an Enterprise Email system and you are getting advice to simply go to a MS Marketing site to find justification. How about the recent report by Radicati, a US based Email analyst firm that stated that Exchange goes down about 4 times as often as GroupWise.
And yes, THE GEEK, Novell GroupWise is still around and it quite popular with institutions like Fire Departments, Police Departments, Hospitals, and Governments. All the types of organizations that absolutely need their information to be available and at a price point that doesn't steal from their more critical budget items.
Mike, it is appalling that you have been hired to provide the best consulting yet simply want to find justification for your preconceived idea of what you want to put in, not what is best for your client.
Mike, you are a Microsoft Tester, you should be able to find enough information from Microsoft themselves without coming out here.
And THE GEEK. Come on, you can do better than that to simply take the easy answer and suggest marketing as a legitimate answer to a serious question.