I love competition, and I started porting my Virtual Machines to VirtualBox 
Here is the BUG
Install any VMWare Workstation
Connect a pen on the host
Open the paint on the guest Windows 8
Use the pen, try handwriting, yes it is not easy, noticeable delays will prevent you
Repeat the same on VirtualBox, no issues at all
Guest and host Windows 8, tablet Wacom Bamboo latest 8 drivers