As a former Omnifocus looking for a cross-platform solution, my choice has basically narrowed down to Doit.im, toodledo and Todoist.
Although Todoist's UI is beautiful in iOS, Android and webapp, its lacks start date support for instance. Toodledo has start date support but is ugly and difficult to get into.
Hence, Doit.im is for now my GTD tool of choice, but there remain a few things that prevent me to go pro:
- Handling of next actions: in omnifocus, there is a choice between sequential and parallel projects. For a sequential project, whenever you complete the 1st action of a project, the next one automatically becomes a "Next action". This is a great gain of time. Also, unless I am mistaken, there is no way to manually reorder tasks within a project. Finally, I think we need a way to quicky "flag" a next action (NA): indeed, not all NA can be done today, and what I usually do is to flag 3-5 actions for the day. With doit.im, I have the impression that the only way to od that would be to add a "today" tag and then filter by tag, but this is a bit inconvenient. I don’t use the “today” list for that because it is a due date IMO, and not all tasks have a due date. Hence, my goal is to create a filter where I have both the tasks flagged and due today.
- Adding tasks by emails: would it be possible to add additional information when adding tasks by email, such as #Project @Context ^Due Date? I have the impression we cannot do that right now.

Thanks!