New kernel release (pvetest repository) with kvm-kmod-2.6.31.6

Is there anyone running Windows Server with virtio drivers on this kernel ?
How are the experiences ?

I run a win2008 64-bit with exchange 2007 and ads. no issues so far but its quite a small installation (around 20 GB email database). I also run a daily full backup at midnight.
 
My experience for using the virtio drivers on a heavy loaded production system is that it is not stable enough:
Testing it a week I am getting several times remarkable slow down of the virtual server (Windows SBS 2003 Standard,Windows 2003 Standard with Blackberry Enterprise Server). Only shutdown and restart could solve this. One time a complete shutdown of two server. Maybe due to heavy load through the backup processes. At the moment I won't use these drivers.