We found all three software options to have an acceptable ease of use, and to be viable alternatives to expensive, commercial, project management software. But, like all contests, there must be a winner...
Project Open: Based on our reviews and analysis, our strongest recommendation goes to Project Open. It has the greatest number of key features, and the highest overall usability rating. Project Open will make a great project management tool for large projects, and for those who need to manage several projects at once. You'll be able to manage tasks, communicate with team members, and track project progress.
Projeqtor: This software has a long list of useful project management features, especially in the area of budget management. However, it's complex tool bar might make it intimidating to novice users, and some tasks require more clicking around to find. The features, while extensive, may not be as robust as those of Project Open.
Redmine: Redmine, though strong in the area of issue-tracking, was found to be the least versatile option for project management software. It lacked the variety of features that most PMs would want. However, Redmine may be the best suited to software development projects and debugging, based on its multitude of issue-tracking features.
Feel free to use the forum below to comment on or discuss our recommendation.