Microsoft has released a new version of the Skype for Linux Alpha every second week ever since the app was first launched back in July. Every single release has introduced more and more features into the app and, while it's still not anywhere near as feature-complete as what you'd find on Windows or macOS, it's actually getting progressively more usable with every release.
Many of the key features have been completed, such as video calling and support for group chats. Various minor things are now being caught up on - for example, they recently introduced the ability to set avatars for group chats and enabling hostless group calling (the ability for calls to persist after the host leaves). It also has a night-mode version which looks quite nice.
The latest release, v1.13, has improved the authentication process of signing into Skype and has introduced the ability to send SMS messages directly from Skype for Linux. Every single release has also come with a swathe of different bug fixes and performance improvements to the Skype for Linux experience and the Microsoft team have been extremely attentive and responsive to issues raised and features requested in the Skype for Linux forum.
If Skype is one of the things that have held you back from switching to GNU/Linux, or if you're already using GNU/Linux and have avoided Skype because it was pretty terrible, it might be worth taking another look at it now.