KVM is more competitive than VMWare
Matt's comment about RedHat needing KVM to be more competitive in this article caught my eye. I've been running a private cloud built on vSphere for several years, and earlier this year took the decision to phase it out and move to KVM, for a number of reasons.
KVM is able to leverage all of the underlying capabilities and qualities of the Linux kernel, and we found it to have matured to the point where VMWare comes out second best in terms of robustness and performance and hardware support. So far, KVM is proving to be lower-cost to operate too, especially as we've encountered serious costs with VMWare due to compatibility problems with leading server manufacturers.
Factor in VMWare's ill-judged price increases this year, and KVM is more competitive for those organisations who have the in-house skills to migrate to it.