How does this offering compares to Google App Engine and Amazon EC2?
VMforce and Google App Engine are both environments for hosting Java web applications and both support Spring which is good news for developers. They can more easily port applications from one to the other. The major difference is in the services provided. VMforce provides a relational datastore service that comes with additional services on top such as search, reporting, dashboards, advanced user security model, etc. Amazon EC2 is an infrastructure as a service offering which is very different. You will have to configure and manage everything yourself except the physical hardware.