The screenshots are here.
I found that this is a very rich tool which allows you to perform various kinds of flowcharts. It also a lot of galleries to help with the various diagrams.
- Very powerful
- Rich selection of galleries.
- Easy to use.
- linking of objects for the lines are easily done.
- Not easy to do a database diagram (needs to be done manually)
- Cannot write notes on the line - have to add a new text object to do that.
OpenOffice Draw is a component of OpenOffice. It is able to draw the basic flow charts and provides those shapes. However, it lacks the other shapes for all the other types of charts.
Microsoft Visio is much more complete. If you go to the higher end version, you can even do things like reverse engineering your database tables or generate scripts to create the required tables. It is also able to scan your network to create a diagram of your network devices. These are things that you may need when documenting your projects.
If your purpose is just to create UML from your application, you can do it directly using: