When I can run vmware server or VirtualBox for free. And trust me: VirtualBox is just as easy an install.
With all the virtual software out there, I think it's time for VMware to at least reduce the price on VMware Workstation. VMware Server does have it's limits but unless you have something out of the ordinary, I think it's better [or at least cheaper] than VMware Workstation.
I will be researching this and I will get back to you with some reasons or with my tail between my legs. lol.