The latest rebranding of the Microsoft Messenger is Skype for Business. Since last year there is an update available that upgrades Lync 2013 to SfB. The new user interface is a welcome improvement, though most of the functionalities have remained the same. There are some nice features like hovering with the pointer over a contact shows you icons for quick actions (email, call etc.), when trying to ring a colleague who is not online it gives you an option to dial their phone number (if available) and it integrates well with a full phone functionality that can easily replace a physical desk phone.
Every now and then MS releases an update that introduces bugs to the application, issues with the UI becoming unreadable to completely corrupting the application that needs to be solved by reinstall. I have also experienced issues with group chats as the chat messages are not delivered to all participants. The last issue I've had was that after an update the Skype meetings started to open in a web browser instead of the SfB application.
In a complex environment with multiple Lync and Office versions it can be difficult to implement. It is best to create a custom package that will take care of removing any environment specific conflicting applications and install together with the dependencies so that the users would have minimal downtime. It can coexist with Lync 2010, so be extra careful about that fact as the cleanup can be cumbersome.
As with many other products, we are deploying Skype for Business in order to continue receiving support from Microsoft. There are some added benefits with SfB, organizing meetings is now easier and more user-intuitive and since we use Lync/SfB as full desk phone replacement it is able to fully perform that duty as well.