I teach an online summer science enrichment course called The History and Philosophy of Science In 6 Easy Steps.
Usually I run it on Moodle, where I run all of my other courses, but this year, I decided to move it to Google Classroom.
I wanted the experience of running a course on Google's platform, and really don't need all the features of Moodle for this course. And it turns out Google Classroom does a great job streamlining the mastery-based learning model.
After reading or viewing a video, students write about it and self-assess. Then we chat about it as a class on Twitter, I assess their work, and they can revise as many times as they want.
Classroom's system of assignment submission and return makes it easy for students to revise and resubmit work. And by automatically creating a copy of the rubric for each student, a copy that is automatically shared with me, Classroom makes it easy for students to submit and revise self-assessments and view my feedback.
You can watch how it all comes together in this tutorial I made for my students: