What do you like best?
Free and open source.
Rapidity of creation.
Diagrams are automatically created
You can use all the main management diagrams needed like PERT, management of tasks and resources.
It allows you to rapidly see what key points you'll have to clear during the project.
What do you dislike?
Lack of flexibility and strange behavior of the interface. Not always well scaled for the Gant diagrams for example.
Lack of personnalisation (Color of the typography / highligh) which can make it difficult to organize things visualy when you have a lot of tasks going on in your project.
Not very easy to share with co-workers.
The menu and interface is quite old though, not very attractive which affects its user-friendliness.
Recommendations to others considering the product
Don't use it as the only software for project management, but it's good for the principal and most important tasks for project plannig. It's a good way to create rapid overview as well.
Look for other complementary software to go with it, like mind mapping tools for example.
What business problems are you solving with the product? What benefits have you realized?
Time management and resource management during project.
Keep track of the progress in time and manage costs.
Anticipating problems of organisation.