Ars Technica posted a review on VMWare Fusion 4

Virtualization has long been important for Mac users, especially those who have to manage multiple platforms for their work. With Apples small share of the desktop market, virtual machines are a necessity for Mac users who cant get by without access to Windows applications.

While virtual machine products from the likes of VMware, Parallels, and VirtualBox provide convenient ways to run Windows and other operating systems on your Mac, Apples recent upgrade to OS X Lion has the software makers scrambling to ship updates. VMware and Parallels have both released new versions that let Windows applications integrate with Lion-specific features such as Launchpad and Mission Control, and take advantage of Apples decision to let users run additional instances of Lion in virtual machines.

  VMware Fusion 4 hands-on: Lion, Windows 7, Windows 8, and more