MindManager and PersonalBrain are different beasts. While they can both be used for similar activities, their focus is very different.
In MindManager you create a single file that is a topic-centered mind map.
In PersonalBrain you create a network that has no center and has links to notes, documents, websites and many other things.
PersonalBrain is great for demonstrating a _network_ of ideas. MindManager is great for describing layers and layers of detail around a specific topic.
To prudnikov, there are some capabilities for project management within Mind Manager. Each node can have dates attached to it and such. And I believe the Gyronix ResultsManager is an add-on that makes ToDo work even better within Mind Manager.