I have settled in Todoist as my main list manager. I have hopes that Microsoft will be the company that solves the email as tasks need. From their To-Do User Voice webpage, it appears that they want to integrate Outlook as much as possible into the app. This, combined with the addition of labels like Todoist, will make this a very nice product. If this is completed, I can see rolling out Microsoft Planner (which will integrate with To-Do) to the key players in my Company and beginning to facilitate a GTD approach within our organization.