So THAT explains way "Virtual Box" is not even mentioned in the article. Those who pay get the editorial coverage?
Take a look at it here. It is a free open source competitor to both VMWare and Parallels.
http://www.virtualbox.org/
I have been using Virtual Box for a couple of years on my Linux desktops ( Ubuntu and OpenSuse). I have been very pleased with its performance. However, on my Mac I prefer VMWare because it seems a tad bit more polished than Virtual Box. And for me that was worth $80.