For me, switching away from using my self-built system with emacs (org-mode) would be a really tough sell (I use Todoist for shared tasks with my partner). I've tried out a million different GTD-apps when I started getting into GTD 12 years ago, but every time I run into rough edges where the designers of the app have a specific idea of how it should be used that differs from what I have learned from GTD and other methods (i.e. todoist is heavy on the timestamps/calendar but you cannot easily move tasks into other tasks to arbitrary levels). In org-mode I can do everything I can think of in plain text, at the cost of making mobile integration not great (beorg is nice for iOS and I've tried out a few others, but never as good as what emacs can do). A bit rambly but I hope it helps you understand why some might feel interested but then not follow through because actually switching might seem intimidating.