That sentence is of course followed by caveats about Python 3 support being experimental at this stage, but all-in-all I think this is a sign that we are finally at the tipping point for Python 3 to start gaining mainstream usage.
Thank you Django community for moving the ball forward for everyone.
Technically, however, it's pretty rock-solid. I'll be launching a site built on Py3/1.5 is about two weeks, and aside from constantly forgetting to `print(...)` instead of `print ...` it's been surprisingly smooth sailing.
It would sure be great to have a list of django sub-projects and their Python3 status.
Regardless, even if we start with Python2.7 and bump up to 3.3 in a few months, this is a great step!
* South doesn't have Py3 support in core, but there's a fork that does and seems to work perfectly: https://bitbucket.org/aaugustin/south-python3
* lxml as of v3 seems to have py3 support (I haven't tried it, but looks like it does).
* simplejson is now in the standard library as "json", so yes there.
* requests works, since v0.10 (about a year ago).
* django-compressor is not ported; however, django-pipeline does run on Python 3 and is basically -compressor's successor. It works great.
* gunicorn works on py3 (as does uwsgi and mod_wsgi, btw.)
* jinja2 hasn't been ported yet.
* twisted is actively being ported right now, and has gotten to the point of "kinda working". You can follow along at http://twistedmatrix.com/trac/milestone/Python-3.x and http://twistedmatrix.com/trac/wiki/Plan/Python3.
* txAMQP probably can't get ported until twisted does.
* django-rest-framework has Python 3 support, I think it's fairly recent, but it works well.
This list is about typical of what I've found doing Django/Py3 work: many things are ported, a bunch more have good alternatives, and a few things are still missing.
The reasons to upgrade to Python 3 are both numerous and serious. If the only hit on your code base is to change "print this" to "print(this)", by all means upgrade. And most conversions are automated -- just run a script named "2to3":
http://docs.python.org/2/library/2to3.html
Asking why one would want to move from Python 2 to Python 3 is like asking how much a boat costs -- if you have to ask, you can't afford the consequences. Here are some of the reasons:
http://wiki.python.org/moin/Python2orPython3
A quote: "At the time of writing (July 4, 2010), the final 2.7 release is out, with a statement of extended support for this end-of-life release. The 2.x branch will see no new major releases after that. 3.x is under active development and has already seen stable releases, such as the recent 3.2. This means that all recent standard library improvements, for example, are only available in Python 3.x."
A more complete list of the changes:
http://docs.python.org/3/whatsnew/3.0.html
Bottom line -- if you don't migrate to Python 3, over time the corner you're painting yourself into will become smaller and smaller.
I only mention this because it's a visible change that's easy to explain in a few words. The more basic changes are mostly subtle and difficult to describe without direct experience.
> but I don't see anything new than, when programming in Python 2x, makes me think "oh, if only I had used Python 3 here!".
That's not a very sound basis for comparative evaluation. If you have only ever owned a horse, the advantages of owning a car might not be obvious. The horse can go places the car cannot, so the fact that the car gets to other places faster might be overlooked.
That's been addressed -- in Python 3 there are now two kinds of division and two operator symbols:
>>> 100 / 9
11.11111111111111
>>> 100 // 9
11
I know that I can use __future__ to sort that out, but when I'm writing something quickly, I often forget that until I work out why my code is misbehaving.