For years we used Wunderlist, for work, including employees without corporate accounts, for family, outside organisation and across continents. ToDo failed from the get go, but to be fair, so do most other tasklist apps, we tried many. We finally moved to Trello - A bit different to Wunderlist and not quite as intuitive, but works across platforms, across organisations. It sadly seems MS loves to destroy good things. Wunderlist was such a good product, we were really sad to see it go.