To echo what was already said, Jabber sort of combines the old personal communicator and ip communicator into one product.
Depending on the organization's needs, you may or may not want to deploy the full UC feature set, as you may have solutions in place. There are key differences in how the two items operate, but at a minimum:
You can deploy in "phone only" mode and run bare bones if this is desired. If you want to add contacts, you have to bring up additional infrastructure.
Jabber does require an account to authenticate and tether the device to. If you didn't have one before, you'll need one now. As noted, if you add devices to an existing user, it changes the license type. If you did not have them tied to a user, and are creating an account to sign in generically, then they are equal assuming the CIPC is erased, as both use an Enhanced license.
The client can use up to 8 lines provided your infrastructure is current enough to support it, however, there are behavioral differences which may be important and require some additional planning. Jabber is oriented around the user, signed into the client. Shared lines with voicemail present a challenge, as do shared lines with calls coming on/off hold.
DNS records are required, but, TFTP options are not.
Once you introduce directory data, you may find the way Jabber uses end user data, versus caller ID data and such, to be a concern if your organizational directory is not in line with the telephone system.
It is harmless enough to create Unified Client Services Framework device, and supply manual server settings to Jabber, to see how the application works and what challenges it may present.
