This is from the 1911 Forum:

These are two totally different design guns. the only thing they have in common is the Colt name.

The Python was a semi-custom, hand built revolver noted as having the best accuracy of all the American double actions.
More time was spent fitting and tuning the action then any other revolver made in America.
Its noted as having the best single action trigger of them all, and the bluing or bright stainless polish was the best ever done on an American revolver.
The Python has the old 1890's Colt action with two hammer blocking safety systems.
The Python frame and cylinder were very strong, but the old Colt design action won't take abuse and continue to work properly.
Like an expensive sports car, it has to be treated properly, but in return you get performance above other brands or models.
The Python is in a class all its own.

The King Cobra is a "machine fitted" revolver that was assembled by selecting parts from a bin until one fit properly.
The King Cobra was built for unlimited use with full-power Magnum ammo, and was probably the strongest medium frame DA revolver ever built, including the S&W 686 and the Ruger GP-100.
Accuracy is excellent but not up to Python standards.
The King Cobra has a modern transfer bar safety and ignition system.
The King Cobra was about a step above every other brand in quality.

Basically, the Python was a Ferrari and the King Cobra was a Mercedes.