When comparing Casual vs Google Tasks, the Slant community recommends Casual for most people. In the question“What are the best cross-platform task apps?” Casual is ranked 67th while Google Tasks is ranked 69th.
Specs
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Pros
Pro Tracks task dependencies using a graph
Pro Great to-do templates
Every to-do list & project can be saved as an amazing template that you can re-use in the future.
Pro Offers a high-level overview of projects
The workflow with dependencies shows where the things are at a glance. No more frustrations of how your project is going and who is doing what.
Pro Sync deadlines to Google Calendar
To-do items can be integrated with your day-to-day schedule using Google Calendar.
Pro Visual way of organizing your work
The workflow includes dependencies and shows you where things are at a glance.
Pro Integration with Google Calendar
Google Tasks integrates with Google Calendar, consolidating your information in one place and allowing you to easily see which tasks have to be done on what day.
Pro Sync With Android
Pro Subtask lists
Each task can have a subtask allowing users to gradually break down a larger task into steps needed to accomplish it. When a user marks the parent task as complete, all subtasks inside that main task will also be marked as complete.
Pro Printable to-do list
Google Tasks allows users to print their to-do lists.
Cons

Con Price
At its cheapest level, Casual is $9 per month for two users and two GB of storage. The trial period is short and there is no free version.
Con Inconsistent sorting when printing
You can start your tests online, but when you print it comes out differently.
Con Can print calendar or tasks but not both
If you want to see your day, you can see both your tasks and your meetings online. However, you cannot print it altogether as shown online. You have to print two separate things.
