I've installed the release build of IE8 on a Vista x86 SP1 system, over IE7, and it seems absolutely fine in acccessing Server 2.0, running on an openSUSE 11.1 host. In fact, it feels crisper and certainly doesn't have the client certificate prompts at initial connect/logon.

I wouldn't like to say that it is an exhaustive test but I changed some host settings, created and booted a VM, got a remote console to it (previously installed with IE7), powered it off and deleted it from inventory and disk. Also changed settings successfully of a running VM. In fact, didn't find anything that didn't work.