Great for time tracking, works the best with Chrome extension plus Android app.
I didn't use all the features available but for my needs it worked out perfectly. Their customer service is very responsive and polite when it comes to inquiries made.
With the TrackingTime Extension for Chrome enhance Google Tasks with time tracking. Get automatic timesheets and enjoy TrackingTime’s in-depth analytics.
Tasks adds a to-do list to Gmail. After adding the lab, click the Tasks link above the chat box on the left-hand-side of the page. Your task list will appear on the right – click anywhere in the list and start typing to add a task.
https://mail.google.com/tasks/