According to the web site for it, which has a pretty good chance of being correct...
Python is an interpreted, interactive, object-oriented programming language. It incorporates modules, exceptions, dynamic typing, very high level dynamic data types, and classes. Python combines remarkable power with very clear syntax. It has interfaces to many system calls and libraries, as well as to various window systems, and is extensible in C or C++. It is also usable as an extension language for applications that need a programmable interface. Finally, Python is portable: it runs on many brands of UNIX, on the Mac, and on PCs under MS-DOS, Windows, Windows NT, and OS/2.
The advantages of using Python are too many and varied to cover them all here, and if you don't already know about it, I highly encourage you to go to the site and read about them.
However, the chief advantage of using Python for Twisted's development is that it has enabled us to keep the code incredibly small. Python's high-level features let us express very concisely the intent of almost all of the Twisted codebase. Less code means less bugs, which means a more stable server infrastructure for you.
All of the developers we recommend for Twisted consulting are extremely well-versed in Python.