PC Magazine published an interesting review about Parallels Workstation 2.1 (not the version for Mac OS X on Intel architecture) assigning a score of 3.5/5 and providing this conclusion:

For those who can do without linked clones, snapshots, and a few other high-end features, Parallels Workstation offers a less expensive alternative to our Editors' Choice, VMware Workstation. It's simple to use and handles straightforward virtual machine tasks, such as running a legacy app in a legacy operating system.

Read the whole review at source.