Unified Messaging

We are looking at Unified messaging and I’m trying to find a review for the vendors I’m looking at. I already found one from Network Computing that is good but it’s over a year old. We are looking at 4 Products. 1. Cisco’s unity 2. Avaya’s Modular Messaging, 3. NEC’s Call Pilot 4. Interactive Intelligence’s Communit?. If you could give me some feed back if you have one or more of these systmes that would be great also if you can point me to a review of these would also be great. Thanks.