In using Data Dude on a project I'm working on, the bizarre situation where a schema compare gives inaccurate results has occurred. The situation was easy to re-produce: one developer made a change in the schema, another developer did a get latest, and compared the project to a physical database that was known to be in sync. Any changes that have come through the latest VSS Get All where being ignored by the schema compare.
It turned out (and it would be nice if Data Dude actually warned you about this before allowing a schema compare) that you need to
build the Data Dude project before it will give you accurate results from a schema compare against a project. It would be best if Data Dude simply detected a build was needed and did it as the first step in a schema compare.
It would also be nice that a schema compare had the (optional) ability to automatically refresh after writing the schema difference from the source to target.
Otherwise, the experience with the tool has been generally positive.