Complete is a to-do app, and there are already many other to-do apps, yes. So... why another one?
Because none of them personally fit my needs - or hopefully yours either!
Complete allows you to create multiple projects within one window, add milestones to each project, and under each milestone, add to-do items. Also, under each project, you can add as many files as you want, keeping all project files in one place. Not only that, you can add notes to each project.
So to sum up the key features: