I've made a living of Python since 2.4 and hitting the 3.6, here is my take on it:
The Python team does an incredible job at making the language evolve. This is a 20+ years old language, with billions of lines written in the world, and allowing a huge number of paradigms. It still matures, steals ideas, makes hard compromise on growth vs compat, etc. I know very few other techs that can even compare to this level of legacy/flexibility.
E.G: the current debate on the mailling list about the "delayed" keyword: https://mail.python.org/pipermail/python-ideas/2017-February...
(Python-idea is a fantastic mailling list BTW. You learn a lot about programming, community management, Python and humans. It's very approachable, yet you read some very talented people. Sign up ! https://mail.python.org/mailman/listinfo/python-ideas)
Coding in 2.x is now a pain. You can't see that if you are stuck in 2.7. 3.X doesn't seems appealing because what it brings on the table is not shinny. But the hundreds of small fixes hugely add up, and the experience is not the same at all on any project that takes more than a few days.
The good things is, Python 3 won. Nobody starts a new project in 2.x, most important 3rd party libs are have been converted and legacy code is ported every day. Porting a big code base is not really hard (2to3, python-future and python-six do most of the work) and can take only a few hours if you know what you are doing. Which is nothing given Guido have us 15 years to do it.
Honestly I had more time porting from Django 1.5 to 1.9 and DRF 1 to 2.
Python 3.6 is a wonderful release and a bliss to use. pathlib, f-string, better error handling, absolute imports, diminished verbosity, transparent unicode support, stable asyncio, unpacking everywhere, improved windows support, wheels for so many things, subprocess pools, pip+venv included (although debians admin excluded them, grrrr)... Everytime you go back to an earlier version it feels clunky.
The problem is, there are very few tutorials showing you the current best practices. I still read plenty of .format(), os.path.join(), manual subprocess/threads handling, etc.
People are still complaining you can't provide a standalone Python program while nuikta have been compiling very well Python for years now. It's even yum/apt installable.
Whether you are in Python 2 or 3 though, the ecosystem makes it all.
I'm amazed at where I find Python these days. It's the official language for colleges in France, it's installed on Linux and Mac by default, on the raspi (en consequently a recommended language for all students in the UK). It's at Google, Facebook, Instagram, Apple, Disney/Pixar, Sony, the CNES, the NASA, Mozilla, Docker...
But also in very heterogeneous places. Blender uses it to script, but most GIS as well. I got clients from everywhere using it: mathematicians, physicists, geographers, sysadmin, bankers, big data analysts, deep learning researchers... In big and small ways.
Plus there are so many great 3rd party tools: requests, django, sqlalchemy, numpy, pendulum, begins, jupyter, httpie, faker, marshmallow, autobahn, crossbar, pew are fantastic.
But how do you discover those ? The ecosystem is so huge, even curated lists such as https://github.com/vinta/awesome-python are intimidating.
On strengh of Python is that it's good a little script upt to big projects. but there is an enormous list of things to learn if you want to get out of the scripter mind set and start coding a big project.
- virtualenv. Wait virtualenvwrapper ? Wait pew ? wait pip ? wait conda ?
- tox, coverall, pytest, flake8, pylint, bandit...
- Python path, modules, __stuff__...
And the packaging is still a mess. It's hard to make a setup.py file for a newcommer. And the 1000 files next to it. It's hard to make a compiled extension wheel. To provide a msi, a deb or a dmg.
It's hard to do desktop or mobile UI. Kivy and PyQT are nowhere as easy as creating a website, which says it all.
Mypy and type hints are not mature enough. Really a pain to use. I would not recommend it right now. Also VSCode and PyCharm makes everything better. I'm a sublime text guy, but the competition rocked it on this one.
Asyncio is super low level. Most people should probably just not use it, it's designed to dev high level libs, not to code your service yourself. And most high level libs using it are not mature. The revolution hasn't happened yet, and we need it to happen in the next 2 years. MeteorsJS is here and kicking. JS has the Webpack ecosystem (which sucks, but provide features you don't have in pure Python right now). You see more and more stack with Sass + es 6 + jsx + whatever and the Python tools to do it don't cut it. So you are back to JS. I hate JS.
Hosting a Python website is still too complicated. pythonanywhere.com comes close, but beginners want PHP + FTP kind of deployments, and you can't blame them. Not everybody needs the robustness of our pro stacks.
Performances, though, has never been an issue for me. I know some people that have indeed the need for it, but my experience is that they are a rare breed. Most people complaining about it want a pony, they don't have a Python performance problem.
Nevertheless, I look forward for the gilectomy just to stop hearing the FUD. But I'm not holding my breath.
I have more hopes for Pyjion, the Microsoft JIT, though. Their approach is the sanest I've seen. Pypy is nice, but is having a hard time by design. Pyston is dead.
Free perf is like free pizza. You don't need it, but hey, free pizza!
Also I have a feeling that rust and Python will be very good friends in the future...