I recently got MSDN access and decided to do some UML modeling for a class project in Microsoft Visio. I have to say, unlike most Microsoft Office tools, this is one where the Open Source community certainly wins. Adding a class, methods to the class, and arguments to those methods to a class diagram, requires so many menus, clicks, and scrolls, that half way through your UML diagram you’ll be wishing you had done it in Powerpoint instead.The slow and difficult to use interface is the main downside. The program was designed to do diagrams, schematics, and just too many things. It does a lot of things, but it doesn’t do them well. To add to that, it doesn’t even have templates for any of the Java datatypes, just C++, C#, and Visual Basic.
The major Open Source alternatives, StarUML or ArgoUML, are a lot faster to use and have all the same major features for UML diagrams.
For Outlook vs Sunbird or Microsoft Excel vs OpenOffice Calc I MIGHT go for the Microsoft version if I can get either for free, but in the case of Visio, I’m going back to the Open Source tools.