The session started by noting that the cloud is ready, the only question is your organization? Skype for Business and Microsoft Teams have a long history and legacy behind them that indicates maturity you can trust.
It was emphasized that a lot has happened with Microsoft Teams in the last 2 years. This is perhaps an understatement. And especially in the phone system feature area, the addition of new functionality is almost hard to keep up with.
Skype for Business and Teams were contrasted: Skype for Business is mostly calling, chat and presence where Teams is a collaboration tool which enrich a powerful collaboration work space.
Teams collaboration in March 2017 was collaboration and now a single hub for communications and collaboration.
Teams with Microsoft Calling Plans or Direct Routing creates a full enterprise calling experience. Calling Plans have the benefit of rapid provisioning, number porting & enhanced 911 and local, long distance and international calling.
There are some ways to get to the cloud without calling plans:
Skype for Business hybrid
Cloud Connector Edition
All these methods allow you to bring your existing PSTN to the cloud.
Some of the capabilities coming to Voice & Calling in Q4 CY2018 which include: