Whenever I have a somewhat complex project to keep track of, I don't reach for one of those traditional critical path method tools -- instead, I fire up Trello. It's free for individuals, and thanks to a very simple card-based user interface for tasks, it's easy for anyone to take a project and break it into workable tasks, then keep track of progress. Today Trello released a native Mac app, meaning that Mac users can avoid the browser-based version.
If you're sharing projects with another person or team, you'll now get native notifications whenever there's activity on a task card. The Trello app support the Touch Bar on MacBook Pro, and any board can be brought up on screen with a quick tap or click (on the Dock icon).
There are shortcuts for creating new cards at any time. That's extremely helpful, as it's common for project planners to suddenly come up with a new task after they've closed out the app. Finally, the Mac app can have multiple windows open for individual boards, meaning that you no longer have to try to remember which browser tab you had assigned a board to.
The app is localized in a ton of languages, and requires OS X 10.9.0 or newer and a 64-bit processor.