Better performance with Compiz Fusion in a VirtualBox VM on Windows 7

First some background.... my previous entries about VMware and VirtualBox:

Compiz Fusion and VMware Workstation 7 not playing nice:
http://orsontyrell.blogspot.com/2009/11/compiz-fusion-and-vmware-workstation-7.html

Compiz Fusion and Virtual Box 3.10 playing together:
http://orsontyrell.blogspot.com/2009/11/compiz-fusion-and-virtual-box-310.html

Today I'm seeing some great performance improvements with the latest version of VirtualBox, version 3.1.2.  Specifically I'm now satisfied with the performance of Compiz Fusion running in a VM on Windows 7.  Previous I'd see delays in the menuing system or delays when typing in a terminal window, but now the windowing performance is fine. 

After upgrading to VirtualBox 3.1.2, I upgraded the VirtualBox Guest Additions on an existing VM, and I also tested a new VM.  In both instances (an Ubuntu VM and a Linux Mint VM) I saw the same performance improvements.