November 09, 2011, 2:29 PM — Fusion 4 is the newest version of VMware's virtualization solution for the Mac, which allows you to run multiple operating systems within Mac OS X. Since we reviewed Fusion 3, VMWare has added support for Lion and the ability to create OS X Lion virtual machines, reduced the consumption of system resources to zero when you aren't running a virtual machine, redesigned the settings window, and much more.
You'll notice one major change in Fusion 4 immediately: it no longer requires an installer. Instead, you drag and drop the application into whatever folder you wish, then launch it. On first launch, Fusion will ask for authorization (which it needs only to change the permissions on some items within its application bundle) and then proceed with initial setup.
At any point in the future, you can move the Fusion application to another drive or folder, and everything will move with it. If you decide you don't want Fusion, there's no need for an uninstaller--just drag the application to the trash, and you'll remove all of it (excluding its preferences file). As someone who prefers control over how and where applications install themselves and their pieces, this is a very nice improvement over prior versions.
One other nice touch: If you're using a MacBook Air, Fusion also ships on a USB key, so you don't need to go digging for your external CD-ROM drive.
Fusion's license allows for unlimited installation on as many Macs as you use (for personal use; business users have different terms). If you use more than one Mac with regularity, this is easier on the pocketbook than is Parallels' "one machine, one license" requirement.
Installing Windows within Fusion 4 is straightforward: Installing the 64-bit version of Windows 7 Professional on a 2011 MacBook Pro (2.2GHz Core i7 with 4G of RAM) took me just under 15 minutes. (I was also able to install the Windows 8 Developer Preview, and it ran quite nicely, too.) Unlike Parallels 7, Fusion 4 doesn't allow you to purchase a copy of Windows from within the program itself. Fusion does include a video that shows you how to buy a copy directly from Microsoft. Even so, you'll want to buy Windows on your own, so you don't pay list price.
By default, Fusion sets up a normal Windows 7 user account, leaving the Administrator account disabled. That leads to more annoying user access control (UAC) prompts, but results in a much higher degree of security. (You can, if you wish, disable UAC to lower the annoyance level.)