As a system designer, would you put VMs responsible for core infrastructure (dns/dhcp/directory/web/wiki/repos/file share etc) and VMs used for development and testing on the same physical machine?
- better hardware utilization - most IT VM has relatively low load
- ability to spend more on better hardware /w $ coming from different projects
- less overall spending
- IT and development probably have different (separate) budget anyway
- runaway development VMs may have adverse effect to core IT services