"With Erlang on Xen, in less than 100 milliseconds after the launch a new node starts to run the application code." -- erlang on xenOne cannot argue that EOX (erlang on xen) launches the application quickly and it's certainly faster than launching an entire guest OS. But surely there are a number of technical reasons why and possibly related to the number of sacrifices that were made in order to get the response time to that level.
Linux containers in the form of docker.io is achieving numbers that are even better and that are not limited to erlang and EVM languages. Additionally your apps do not give up the filesystem which you are used to.
UPDATE: The equivalent hello world running on a rackspace server took 20ms. (2013-06-30)