The fact that ressources, workload, and planning can be adjusted with Instagantt. The easy way to handle the software. The overview that sum-up the situation.
Instagantt is a great tool for detailed gantt features like baselines, subtask view/hide option, keeping lag between tasks, zoom option. Kanban has potential also, you can have cover picture, it shows if there is any subtask on it, and progressbars. And basic budgeting feature is also available. You can see easily easily what was estimated and what the real cost is which is important!