I was invited at the Convergence 2008 conference on Virtualization at the IIT Bombay. I thought it would be fun to have competitors looking at you while you tell everyone why your hypervisor is the best. It was a slight disappointment, though, as Citrix (Xen) and Microsoft were absent. VMWare was present, however, and quite a lot of people who have used Xen.
The problem with KVM is people know about it, but not much information is available by way of whitepapers or nice graphs showing why KVM is better than the others. So not many try it. That's really sad, since KVM is so simple to learn, use and adapt that it should ideally be the first thing that comes to peoples' minds when they think of a virtual machine monitor. And since KVM believes in the UNIX philosophy of 'do one thing and do it right', we automatically inherit several features from the environment that already exists, for which the competition has to spend years and a lot of dollars to get support for. For example, guest memory swapping, NUMA support, hibernate/suspend/resume of the host machine with VMs on and so on.
The slide deck on my KVM presentation is available for those interested. People searching for more KVM information: see the KVM Forums page. As of now, there is quite a lot of information present in the KVM Forum 2007 page. The 2008 KVM Forum is happening in June, watch the kvm-devel mailing list for information on what to expect and how to get there.