Running in VM
Seemed to run fine under Hypervisor 1 core 768Mb RAM. Installed size about 12Gb.
Funny thing I discovered when installing at home; Windows 7 Virtual Pc is limited to 32bit guests. I loaded it under Virtualbox instead, to have the developer tools.
Overall I'd have to call the Metro interface a new Start Menu, not a new interface.
Our web application depends on a 32bit ActiveX viewer, which ran fine under the 32 bit IE (not the default), as it does on Vista and Win7 64 bit OSes. I was able to add a shortcut to the Metro Start Menu, but after closing IE, it returns to the desktop, rather than the Metro. I suspect that behavior will change closer to release, and may end up being selectable (for the manufacturer any).
FYI - Hypervisor is an option in Windows Features. Since I am running under Hypervisor, the core option was disabled.