Cisco Unified Communications can be used to connect all your offices using VPNs between them.
With SIP enabled you can make voice or video calls in Unicast and multicast sessions.
Call routing can be performed very easily on this device.
The URI dialing feature allows you to make any to any dialing.
It also has powerful speech recognition which is better than any other speech recognition software.
The single digit dialing works like magic. You can reach important people of your organization by just pressing one button. It also works with the soft communicator where you don't need to differentiate VLANs.
You can create partitions in CM Dial plans. You can control who calls you or who you call.
Also adds a lot of security to your organization's voice and video infrastructure.
Also includes centralized management.
Room for Improvement:
A few of the important features are available only Cisco Unified Call Manager 4.0 or above.
To have 2 call management server configured as failover would be expensive.
The best feature I would say about Cisco Unified Communications is the Telepresense.
With Telepresence you can get high definition video and get the feeling of being in the same room even though the other person is miles apart. This technology is being adopted by a lot of organizations for meeting purposes.
This will make you feel like the other person is sitting right next to you.