I’ve been using Parallels Desktop since the first public release. Although their Windows support gets better with each release – I love coherence mode in the recent betas, their Linux support remains abysmal. They still don’t have Parallels Tools for Linux, which keeps the virtual machine’s clock synchronized and lets you move the mouse in and out of the VM window freely. Furthermore, when you create a Linux VM, they don’t even have an option for Ubuntu, the most popular Linux distribution. Instead I have to use either Debian or Other Linux.
I tried the VMWare beta and found that it works beautifully for Linux. They even have VMWare tools for Linux. Unfortunately there’s no coherence mode, so it isn’t as nice for running Windows.