Simply the best to-do app out there. Fits greatly with the GTD methodology, allowing the right amount of flexibility without never over-complicating it.
The UX, even years after the initial release, is still unmatched. And it's just a joy to use.
Things 3 is the best to-do app you can use without a mouse. My favorite keyboard shortcut is Ctrl + Space, which lets me capture to-dos even during intense meetings.
Pretty. Lovely. Consistent. Also, trapping, unsustainable, lacking and über-slow to evolve. I've had a love-hate relationship with Things since their very first version, up until their last release. I got tired of waiting and compromising with other apps to do what I need. Leaving Things3 was a real nightmare, as I had so much in there. CC chases highlights in the AppStore to exist, and has little to no interest in user feedback. A very expensive one-thing only tool, at times where everyone in the room is smarter. If only others could copy it's perfect parsing add task extension.. I am far and well away from it.
Absolutely love Things, and utilize it as my go-to for managing all my tasks personally and professionally. Only issue I have revolve around collaboration features. Would love to fully merge all task management into Things, but cannot do this with collaboration features (sharing, commenting, attachments, etc.)