[Porsche-O-Phile]

The prefab units aren't bad but you're really not going to save that much versus wood framing like Souk said... You'll end up with the same permitting issues and costs, etc. The only immediately obvious advantages are non-flammable construction and simplicity of construction.

I like being able to design/build what I want however. The variety of the metal structures is pretty limited - at least the ones I've seen. I imagine they're a PITA to insulate if you ever want to down the road also...