Google Duo vs Skype

Google Duo
Google Duo is the new, simple video calling app that brings you face-to-face with all the people that matter most.
Skype is a software application that allows users to make voice and video calls and chats over the Internet. Calls to other users within the Skype service are free, while calls to both traditional landline telephones and mobile phones can be made for a fee using a debit-based user account system. Skype has also become popular for its additional features which include instant messaging, file transfer, and videoconferencing. Skype alternative for enterprise is called Skype for Business. Secure Skype alternatives are Signal and Telegram.
Skype has better video than Google Duo

2018 - Google Duo gets video- and voicemail to keep up with Skype

Google’s messaging app Duo now allows to leave voice and video messages when nobody picks up your call (or politely declines to talk to you). Duo users can leave up to 30-second messages and your contact will see them in the Duo app. After watching the video or listening to the message, your contact can call you right back, at which point you can decide if you want to pick up the call or just let it go to videomail, too. Google notes that all messages are end-to-end encrypted and that the update will start rolling out to Android and iOS users today, and that all users worldwide should see it within the next few days.