If you are not "Virtual Box savvy", then I would advise it. At the risk of starting a flame war, Virtual Box is not as intuitive and end-user friendly as VMWare. I am an expert at both, but Virtual Box requires a certain amount of advanced understanding in order to use. But, Virtual Box is completely free, so people want to use that as a first option.
You can download a free trial of VMWare Fusion and use that to get working with Landshark, and spend time becoming more familiar with Virtualbox later, if you so chose.
That being said, several people are using Landshark on VirtualBox.