Unity 5.x gives you access to more features within Unity for the subscribers and administrative functions.
- Subscribers will have more features available to them.
- Unity 5.x supports Exchange 2007 clusters, Unity 4.x does not.
Between Exchange 2007 as a UM platform and Unity 5.x, there are differences you need weigh on.
- if you have extensive call handlers setup with Unity, you will be limited with Exchange 2007. Unity is way more flexible when it comes to customizing the subscriber and caller expierence compared to Exchange.
- Microsoft basically says this is how Unified Message is to be and that's it. There is very little to customize on the platform or be able to customize. This may be a good thing, or could be bad thing. If your company has used Unity for years, and have built it around your business functions and processes, expect to be a huge change for how this works in Exchange.
- Im not sure if they have resolved the MWI issue, but I know 6+ months ago, you needed to by a third party software application and license to run the MWI lights called Geomant. Added costs.
- Each system has pros/cons. I would advise to have a bake-off and see what works for your case. Features/functions vs business drivers and processes. For example, if having flexible call handlers, customized directory searches and the not having another vendor involved in your voice infrastructure (example) then Unity is the way to go. If you like bells and whistles, Exchange has plenty, but falls short of what Unity can do overall.
Unity Connection is another option to compare as well. Unity Connection will be close to Exchange 2007 bells and whistles soon if not now. I think once Cisco updates the voice recognition engine, it will be even keel. What Unity lacks is a good VR engine. It has not evolved for whatever reason. Cisco does offer another server to handle the VR engines (speaking to Unity to say "delete" "next" speak directory name, etc) but it's limited. Exchange's engine has many more features.
But again, I think the whole Voice engine is a bell and whistle. It's not a huge selling point when it comes down to the business drivers I believe.
Anyways, if you search the forums, you will find more information as well. i know this topic has come up before.
cheers
