I started with GTD and 2Do and just recently started to use Toodledo. I'm very happy with it so far. Syncs very well. I only hope that the Android version of 2Do will support Locations in the near future.
My folders were based on the lists in GTD, but after reading about Kanban I split the Next Actions into:
- Things to do after a week
- Things to do within a week
- Things to do Today
- Work in Progress (WIP)
Just changed that two days ago, so I have to see whether this is working for me. I might combine Things to do Today and Work in Progress. It seems a bit of a waste of time to change the folder from ...Today to WIP for a task of only ten minutes for instance.