I have installed Parallels Desktop on both Windows 7 Pro. and Ubuntu Karmic. 2 guest operating system was my test case, which were Windows XP Pro. and Ubuntu Karmic (again ). By the way I have licences for all operating systems I use both as host and guest. Quick and dirty way of telling my observations to you is a pros and cons list i guess.

Pros:

- Automatic installation of Windows systems (Requires you have a licence of guest OS)

- Simpler shared folder management

Cons:

- Bad performance compared to other virtualization products

- Similar product is free (VirtualBox) but this one is commercial

- Really bad visual performance and responsiveness

- 3D support doesn’t worked out of the box on Ubuntu Karmic guest.

- Linux version’s performance is good but of course if you can make it run!

Results: Short way, there is no need to pay some bucks to commercial software while you have a better one free, VirtualBox. Looks like a fine system if you are planning to use it on server virtualization because non-graphical application performance is really good and supervisor have an option for dynamic balancing of system resources. But for a workstation virtualization this software is far from perfect. Linux installation is easy but installing and running guest OSes is a head ache. Also have a USB driver problem on linux hosts which ends up with a frozen system. My opinion is give a chance on Parallels server systems but for desktop virtualization use VirtualBox.