Pre-Fab/Modular Construction

[Mike Woo]

Hello All,

Has anyone had any experience building with pre-fab or modular construction? There are new pre-fab firms doing exciting stuff with innovative designs:
http://methodhomes.net/
http://www.projectfrog.com/

There seem to be a lot of benefits such as building in a controlled environment, cutting down construction time (which mean getting to market faster, lower construction loan interest, etc.), faster permitting. Modular construction has been around for a long time, but is still not a very common form of construction. What are you thoughts of building modular spec homes, townhouses, for example in an urban environment?