It has a very good pedigree. It started life as Project Management Workbench
(PMW) in the 80s, which was a very good product. It was centred around
project management (which many others aren't, unbelievably), creating a
plan, and managing that plan as the project cycle invariably creates change.
Unfortunately, although PMW evolved functionally, it never created a version
with proper windows integration, and lost ground as a result. In the 90's it
turned into a Windows scheduling tool with a database to store the projects,
called 'Results Management Suite (RMS). This then became NPM (Niku Portfolio
Manager) when ABT were bought by Niku. The scheduler, now called Niku
Workbench, went on to be the core of Niku6, which was, Workbench apart, web
based. Niku6 then became Clarity, then Niku were bought by CA, who
open-sourced it and called it OpenWorkbench.
I have been using these products since the mid-80s with PMW, and think it is
a true project management tool. MS Project is a good tool for creating plans
and Gantt, and integrating into other windows products, but is not a true
project management tool. GanttProject is just trying to be open source MS
Project IMO.
Bob