What's great
Love to track my time and have used everything from RescueTime to Toggl. DoneThat does away with manual tracking (in comparison with Toggl) and improper categorization through low-dimensional data (in comparison with RescueTime). I wish it synchronized more directly with Google Calendar since that is my source of truth for everything. As a result, I've built a converter that can take their output format and synchronize it to Outlook, Yahoo, or Google Calendar through .ics file conversion. http://donethat.kran.ai/.
vs Alternatives
I use so many different apps in so many different contexts that having rich annotation of the data through AGI is the only logical choice. I used Rewind when it came out but then they pivoted to something boring, I've used RescueTime for a long time but it only knows which tabs are open, and Toggl was my old manual solution for client work which was a joy to manually annotate since you set an intention but it's hard to keep up with in a professional environment where your hours aren't invoiced.

Toggl
RescueTime