[...] But the fact remains that Apple has buried the A & I feature in obscurity rather than explained how it has evolved.
I would say that A&I is not buried, but so obvious it is easy to miss!
As the above poster indicates, Archive and Install is the "normal" installation option with Snow Leopard, which was not the case with Leopard. Also, since SL has the ability to download, if needed, certain drivers, etc. that might normally get lost in an Archive & Install, this version is even smoother inoperation than its predecessor.
