[antiRepublicrat]

I tend to see XEN where the PERFORMANCE of the OS instance is the primary concern or where there are limited funds for the virtualization software.

I seem to remember Xen having the ability to do effectively instant migration from one physical host to another over the network without a noticeable loss of service. That's a serious enterprise feature. Does VMWare have this?

[taxcontrol]

VMware has a similar function but I have not personally used it so I can not attest to the migration time. The VMware product that enables this is call Vmotion.

Here is their web site for Vmotion.
http://www.vmware.com/products/vi/vc/vmotion.html

[zeugma]

I seem to remember Xen having the ability to do effectively instant migration from one physical host to another over the network without a noticeable loss of service. That's a serious enterprise feature. Does VMWare have this?

I can personally attest to the VMotion feature working as advertized. It's freaking amazing. We've actually done tests here where we moved from one physical server to another during the middle of a major windows upgrade, and it worked flawlessly. I'm fully impressed with it.