We
virtualise a few servers at work and it pays dividends in many
ways.
We can move virtual servers between physical servers with a few
mouse clicks. We can spin up new instances with ease and you can
create snapshots and go back to them when / if you need.
We run MS but are considering moving to VMware because we cannot
run Hyper-V on our older servers at the moment.
Virtualisation works better if you have a SAN to share between
physical servers when it comes to moving virtualised servers
between boxes but you can also get away with just copying the vm
disk however this is much much slower (but cheap and anyone can set
this up).