Good but needs fixing...
The Sort by Availability in Options never stays as a preference. I have to turn that on every time I use Lync. Chats disappear randomly. You can exit Lync and sometimes they are there when you return and other times not. So many great features but somethings frustrate. Hide all the people who are not online or move them to the bottom by default.
More Distinct about
Skype for Business, v5.6