I've tried the most popular apps like wunderlist, Omnifocus and cultured code things... All very good, but way too complicated or they lacked something I needed... The fact that goodtask is build on iPhone reminders makes it work flawlessly with Siri, calendar and Apple Watch... And it costs a fraction of the other apps. The iOS app is actually free (you can support the developer if you want) and just pay for the OS X app. Great work!!