It is ironic that toy todo apps are a favorite way for programmers to learn a new toolkit, but I can’t find the perfect real app, and may end up building it myself. I’ve been daydreaming on the ideal app ever all the way back in 2005 (then I would have wanted it for the PalmPilot) and then 3 years ago I was taking a deep look at Apple Reminders as a possible substitute for AppiGo Todo, which I’ve been using pretty much since iPhones had apps. (I remember a big wall poster in the apple store showing the built-in notes app being used for a todo list, back before there was an app store or the default Reminders app – an odd reminder that the 2007 iPhone was a serious step down from the 1996 Palm in terms of being a PDA until Apple got its Appstore going.) More at Kirk’s UI Blog.
Excellent stuff as always from Kirk. My recommendation is 2Do on iOS and macOS. Does everything I need with just the right balance between efficiency and understandable visuals.