There shouldn't really be too much difference in performance, perhaps besides the drivers available for the host's video so proper acceleration can be utilized. I have used both VMWare on Windows and Linux (as well as VBox more recently) and I have not really noticed any pertinent differences.
As someone else mentioned, the only obvious benefit would be that linux has a much smaller overhead to run as compared to Windows. So you should technically have more resources free to run more virtual machines. In regards to linux distro it shouldn't really matter, but Ubuntu anywhere from Lucid Lynx (10.04) forward would be a good starting point.