The reason is that it works very smoothly across my iPhone, Mac, and iPad, and I don't have to pay for it.

I don't use my calendar to strictly manage my tasks (I do them as soon as I think of them, and if something can be done tomorrow, I'll leave it for tomorrow and look at it again tomorrow), so I use Apple Reminder to make a note of things I need to remember.

Me either, i wanna try!

I'd like to know why you choose Todoist, not Apple reminder!