Its hard to compete with a partner when your product doesn't measure up
Don't forget with all the sword rattling that Citrix still partners with VMware, and sells cooperatively to many customers. Reference this article from last September. Virtually nothing has changed since then (pun intended) except Microsoft delayed the Viridian ship date (again)...
http://searchitchannel.techtarget.com/news/article/0,289142,sid96_gci1272665,00.html