@Gabz I get many tasks and things I need to follow up on via email. I forward them all to Things.
I also get many tasks that are due in say 3 weeks, but I need to be working on as I have time.
This is where I really rely on start dates. It allows the task to show up in my today list, where I can see it and be reminded to make some progress, and if I don't finish it it just carries over to the next day, or.... If I know I won't have time to do that task today, simply change the "when" date to the next day.
I still like to keep up on other apps features, but the way things works just clicks with me.
If todoist would add start dates (unlikely) I would probably switch.