I've been on the VMware bandwagon since the 3.X days and for awhile they were king.
However MS has stepped up its game bigtime with the latest incarnations of Hyper-V.
I would expect VMware to lose a large marketshare over time to Hyper-V.
I could care less who wins out in the end, as long as it makes my job of managing systems easier that's who I will recommend to managers to purchase for us admins to use. I have no loyalties to any software company.