We have a Communication Manager cluster with almost 200 phones and 150 softphones (Jabber). All call handling is done with this solution. We have it integrated with Active Directory. This solution was added to the Unity solution for voice mail integrated with Office 365. The Expressway C & E solution was also incorporated for the registration of softphones (Jabber) from the Internet in a very simple way for end users. Finally, we have the connection to the PSTN through a gateway with SIP trunk.
Using the Communication Manager, it gave us the possibility to move around the office, and even outside the office, keeping our phone number always accessible using Jabber. This is essential to be able to apply it from the home office without problems and without having to always have a connected VPN.
Additionally, it improved communication between collaborators a lot when using video calls with Jabber, since body language greatly improves communication, making it richer and shortening the time necessary for a call.