Recs.
Updated
SpecsUpdate
Pros
Cons
Con Problems with the official Android app
For a long time there was no official Google Tasks app for Android—though there were some good third-party ones. When an official one finally debuted, it didn't support indented sub-tasks, and using it would destroy all indentation in any category you accessed.
Con Cannot have Tasks and Reminders
Google tasks is simple and integrates with Calendar quite well. But typical of Google they get close and screw it up at the finish line. With Google calendar you have both Tasks and Reminders, but you cannot have both? Also, you can divide tasks into separate lists (say on a per project basis). That's great, but (there is always a but), Calendar will only show one list at a time. So to make sure all your tasks are visible you have to put every task into a single list making the feature, well, useless.