gregtyree.com

Nice piece on the performance of various VM’s available on the OS X.

From a pure performance perspective, Fusion proves to be a faster performing platform than Parallels. Additionally, in our anecdotal hands-on testing we found Fusion to be somewhat more stable than Parallels–which is not necessarily a fair comparison, as we’ve spent more time using the shipping version of Parallels than we have Fusion. Usability between Fusion and Parallels also differs slightly, and personal preference will likely depend on individual tastes–I find Parallels a bit more intuitive than Fusion, but this could also be a function of my having spent more time with Parallels. CrossOver still has a lot of catching up to do, but the folks over at CodeWeavers appear to be making progress all the time. To date, mainstream gaming on the Mac still has only one significant outlet: using a native Windows install via Boot Camp. All that said, if you all you need to do is run more pedestrian Windows applications on your Mac, such as Outlook or Excel, you are not likely to notice significant performance differences between any of the virtualization options mentioned here–for less resource-intensive applications, the performance of any of these virtulization applications is probably fast enough.

Inside CNET Labs: Windows virtual machine performance on the Mac | Crave : The gadget blog