Coming from an enterprise systems background (think Java and Windows) - I'm surprised at the popularity of python as a prototyping language and am trying to put my finger on the precise reason for this. Examples include being listed as one of the four languages Google uses. Possible reasons include:

* enables rapid systems application prototyping using of c++ libraries using swig wrappers
* built to a well defined language specification
* innovative features at the syntax level enabling high level of expressiveness
* highly flexible web frameworks built long before other languages (django)

The questions is what makes it so popular/highly regarded, but to give some balance I'm going to give some reasons it might not be popular:

* less tool support
* less enterprise support (ie a vendor helpdesk)
* lower performance
* BDFL not caring about backward compatibility in version upgrades

Or was it just the best at a particular point in time (about 8 years ago) and other languages and frameworks have since caught up?