App Name: Astrid Task/To-do List
Description: Astrid is a very popular task/to-do list app on Android and iOS. It features reminders, lists, sync, a widget, task sharing, optional instant notifications. With this app, you can sync with Astrid.com, sync with Google Tasks, and sync with Producteev.com. There are also a couple of paid ad-on apps available to increase your task management.
Developer: Astrid Inc
Astrid Task Todo List Android App Review by AndroidTapp.com (older but still gives good basics)
Astrid to-do list manager – Android app review (video) LifeOfAndroid.com
Android and Me Video App Review – Astrid (Task Manager) AndoridandMe.com (older but still gives good basics)
Be More Productive With Astrid Task -AppStorm.com