Parallels 6 above running Windows 7 64bit Ultimate Edition and Windows XP on a Mac Pro/Mac OS X 10.6.4 running Photoshop CS5 Extended – click the image to enlarge
Most of my day to day work is done in the Mac OS. However, there are times when I need to run Windows app/utility here and there. I can remember the days when I used to carry two laptops for work. I had a PowerBook for doing demos to Mac customers and an IBM (now Lenovo) Thinkpad for doing demos to Windows based customers. Once the the MacBook Pro hit the scene I was quick to jump on board because I could now use this one laptop to run both Mac and Windows Apps. Apple allows you to enable a feature called "Boot Camp" right in the Mac OS itself. With Boot Camp you setup a partition (size of your choosing) and natively install a copy of Windows (not included) on it. Then you can choose to boot up the computer in either OS and Windows running under Boot Camp is just as fast as running Windows on any other similarly spec'd PC. While you do get to run Windows as fast as your Mac hardware can, you have the disadvantage in that you can only run one OS at a time. In other words while you're booted in Windows in Boot Camp, you don't have access to your Mac apps. This is where virtualization Apps come in. The two top contenders are Parallels and VMWare's Fusion. I've had experience with both Apps in their latest versions and given the choice I'd go with Parallels.
When you have two apps that basically do the same thing, you have to look at "how" they do it?
Both Apps are great and both apps have very similar feature sets. Although I get to use VMWare's Fusion at NO COST TO ME because my company has a site license and offers it to any employee that needs it, I prefer to use Parallels (and buy it out of my own pocket). Both Parallels and Fusion allow you to use Windows on top of the Mac OS. This means that you are running both OSs at the same time and can launch apps in either. Both are going to run a bit slower than running natively in Boot Camp if for no other reason, they are sharing resources with the Mac OS running at the same time. However, being able to run the occasional Windows app without rebooting is worth the small performance hit. Both apps allow you to either run Windows from a "file' on any hard drive (including an external drive) or even use your Boot Camp Windows installation. So if they both seem to do the same thing, what makes one better? SPEED!!! Parallels with version 6 continues to have the advantage over the competition with SPEED! No other way to say it other than it just runs Windows FASTER. According to Parallels, version 6 is up to 80% faster than version 5. It's 64 bit and boots Windows more than two times faster than Fusion 3.1. Parallels 6 scores more than 2 times better on 3D graphics than Fusion 3.1.