We were looking at going from Lync to Skype because it is the "next" thing, but Skype has some issues with various OS and Office versions we have deployed. It also kills the older chat clients, leaving people cut off if you can't complete the rollout all at once. If we go Teams we get the brand new experience (for better or worse) but can leave the old chat client there for people to use during the rollout. It is Teams for the whole company, and in a smaller scale IT has Slack in case the Microsoft stack fails.