Xen vs. Vmware?

Hi List; I want to run CentOS within my SuSe 10 install. I have vmware 5.5 installed however I wonder if Xen is a better option. I have a xen grub boot option when I boot but I know nothing about how to setup an OS within it. Can anyone point me in the right direction and/or give me your opinions per xen vs. vmware? Thanks...