Despite being a Mac fan for as long as I can remember I have always been intrigued with the ability to boot multiple operating systems. When Apple came out with the Quadra 630 and PowerMac 6100 models that had optional DOS cards in them, I was awed at the notion of quickly being able to switch over to Windows with a keystroke, and have since tackled many options for running other operating systems on my Macs, including emulation and the now popular virtualization solutions enabled by the current Macs' Intel hardware. There's something just fun about being able to boot and use multiple operating systems on a computer.
The three most common virtualization packages for the Mac are Parallels Desktop (being the first on the scene) and VMWare Fusion (which also was a long-time player in the virtualization game), as well as Sun Microsystems' "Virtual Box", which is a free and robust alternative.
Recently, with the release of Windows 7 these companies have been hard at work keeping their programs compatible and optimized for the new environments. VMWare released version Fusion 3.0 a few weeks ago, and being a Fusion user I was quick to upgrade my installation and give it a try. I had already installed Windows 7 in the previous version of Fusion, and it seemed to run great with the exception that advanced graphical features ("Aero") were disabled. Nevertheless it installed and ran, and I looked forward to the 3.0 upgrade which promised to bring the missing graphic enhancements.
I've been running Windows 7 for some time under VMWare, and despite various configurations and reinstallations the program does not perform well when the advanced graphics are enabled. There are extensive discussions at the VMWare support site regarding this issue, and it is clearly a work-in-progress. I look forward to the bugs being ironed out of it, but meanwhile if you are a VMWare user you can disable the advanced graphical support and still have a good experience running Windows.
On a side note, I did find out through this experience that the Windows "Experience" benchmarking that Microsoft introduced in Windows Vista does not reflect performance very well. When the advanced graphics are disabled and the system is running smoothly, the windows experience claims the lowest performance possible (1.0 out of 7.9). However, with the graphics enabled the experience index jumps to 3.6 even though the system is chopping and lagging, and is essentially unusable. Oddly, the only component that shows an increase in performance is the graphics section of the benchmarks; the rest such as CPU and RAM performance show minimal changes.
On the Parallels side, version 5.0 of the software has just been released, which like VMWare Fusion promises to bring the full "Windows Aero" experience to virtualization users. I hope they have done a better job with their implementation than Fusion, but we'll wait and see. As with Fusion 3.0, the latest version better integrates into the 64-bit kernel environment of Snow Leopard, and provides more hardware resources to the virtual machine.
The full list of improvements in Parallels 5.0 are listed here in this support discussion thread, along with user questions and responses from the Parallels team.
CNET Editor Jim Dalrymple has an article on the new version of Parallels Desktop, discussing the speed improvements and the new "Crystal mode" feature. Check out Jim's article here: "Parallels 5 boasts huge speed improvement"
Sun's VirtualBox application was also recently upgraded to version 3.0.10. Unlike the recent Parallels and VMWare announcements, this is just a minor upgrade to a version that has been out since June, but does bring a number of bug fixes and enhancements to the software. Most notably is support for a few features for Windows 7 and various Linux distributions. The VirtualBox changelog can be found here. It is a free project with ongoing development, and I am eager to try it on my system. As with the potential for incompatibilities with antivirus software, I have been hesitant to install multiple virtualization packages on my system at the same time; however, according to several users they both should run just fine, even when launched simultaneously.