Beside using Python 2 or Python 3 for my development activity?
Python 3 is the future of the language. Guido van
Rossum (the original creator of the Python language) decided to clean up
Python 2.x properly, with less regard for backwards compatibility than
is the case for new releases in the 2.x range. The most drastic
improvement is the better unicode support (with all text strings being
unicode by default) as well as saner bytes/unicode separation.
Besides,
several aspects of the core language (such as print and exec being
statements, integers using floor division) have been adjusted to be
easier for newcomers to learn and to be more consistent with the rest of
the language, and old cruft has been removed (for example, all classes
are now new-style, range() returns a memory efficient iterable, not a list as in 2.x).
The What's New in Python 3.0
document provides a good overview of the major language changes and
likely sources of incompatibility with existing Python 2.x code.
However,
the broader Python ecosystem has amassed a significant amount of
quality software over the years. The downside of breaking backwards
compatibility in 3.x is that a lot of that software doesn't work on 3.x
yet.
