Hi Aen - We have been using Windows 2008 servers with VirusScan 8.5i in our EPO environment for a number of months. No problems so far. Just remember that you need to update up to patch 5 to ensure full Windows 2008 compatability.
And if you are in an EPO environment, note that if you install EPO Agent 184.108.40.2065 to your Windows 2008 server, you will need to update it to patch 7.
We have only just begun trialling VirusScan 8.7i on a couple of laptops so I have no feedback for that version.