Nos mandan de IBM un artículo que muestra las diferencias de las versiones anteriores de Python con la nueva versión 3:
Python 3 is the latest version of Guido van Rossum’s powerful general-purpose programming language. Whether the Python community will accept version 3 is anyone’s guess. The breaking of backwards compatibility will mean supporting two different versions in parallel. This article covers changes to input/output (I/O), the new bytes data type, changes to strings and string formatting, and finally, changes to the built-in dict type.