Extremely disappointing. Call video quality has been pretty consistently worse than Hangouts, and it has significantly fewer features—you cannot even rotate into landscape on mobile or full-screen other people's video on desktop. I literally only tried Duo because Google Meet (the app Hangouts forces us to use for video calling now) forcibly ends calls after 1 hour, but having to restart the call every hour is better than dealing with the limitations of Duo. (Also, not an issue with the Android app, but if you are calling non-Android users, the browser(/Chrome OS) version is annoyingly laggy when you select to join or leave a call.)