I've used Astrid for a while now. Definitely my favourite to do app. If you get the donate version you also get the add ons, including backup. This is incredibly useful for me as I often reflash the roms on my phone, but as long as I've backed up astrid and saved the file to my pc I can get back all those little jobs that must be done.

Good to hear, please email the dev that you want some kind of backup/sync with the app :< Maybe if more people bug him on that...he'll add that feature.