Flipgrid. Kids can record directly in the app (or website) or they can upload their own video. Plus all the videos are in one place and I just click next. If I'm checking for note accuracy on longer videos I'll listen at 1.5 speed and only go back in real time if I need to correct something that they missed. You create the classes and topics (assignments) and can control whether the rest of the class can see and respond to other videos. You can also send text or video feedback to the student.