It seems as though the ILS and its variations have been a hot topic lately in some of the "real world" forums. I'd like to say I know it all verbatim but I have to admit I do a lot of research for some of my responses. I found this recent article very interesting. When reading this excerpt, those who are paying close attention will notice that, he refers to the Aztec as a "cub". I believe this is a reference to public perception (any Piper must be a Cub) and not a typo.

AOPA/Proficient Pilot APR-05/Barry Schiff

".....the conventional ILS is called a category I, or CAT I, approach. It has a decision height (DH) of no less than 200 feet and requires a minimum visibility of no less than a half-mile (or runway visual range, RVR, of 2,400 feet near the touchdown zone). An exception allows us to make an ILS and land when the RVR is only 1,800 feet if the runway has centerline lights.

In 1962 and in response to a growing need by the airlines for reduced approach minimums, the FAA issued a notice of proposed rulemaking (NPRM) that sought comments on what eventually would become known as a CAT II approach (with a DH of 100 feet and an RVR of 1,200 feet) Then-AOPA spokesperson Michael V. Huck responded to the NPRM by stating, "Light aircraft are more maneuverable and can operate more safely under lower minimums than can transport aircraft."

Huck persevered and ultimately became the first general aviation pilot to be certified for CAT II approaches. This set the stage for the drama that unfolded at John F. Kennedy International Airport on April 2, 1968.  The reported weather consisted of a 100 foot ceiling and an RVR down to 1,200 feet. This forced jetliners to divert while others-- I was a copilot aboard one of them-- held helplessly, hoping for conditions to improve. Huck arrived in the area on a personal flight from Washington, D.C., and neither diverted nor held. He instead guided his Piper Aztec toward the runway and made the first-ever CAT II approach at JFK. (You cannot imagine how embarrassing it was for the captain to tell our Boeing 707 passengers that the only aircraft to land at JFK that morning was a Piper Cub). .........."