Yes, really. What if the library you are using uses blocking IO? What if it reads a file using a plain 'with open("file") as fh:'? Now you've blocked every connection in your twisted server. No warnings or errors, just strange intermittent pauses on every connection leaving you scratching your head.

This isn't weird esoteric packages either. Ever used requests? SQLAlchemy? Django's ORM? You can't use them with twisted.

Twisted proponents don't openly say this up front as it's not a great story, and their response is usually "just" port the library.

Or maybe, put it like this. If Django and Twisted work well together, why does Hendrix exist at all? Just use Django. Or why does klein exist? Just use werkzeug. You'll see lots of this rewriting snowflakes.

Just a quick search gives me txamqp, txmongo, txmandrill, txflask, txcelery, txdocker, txldap, txgithub, txrequests, txstripe, txzookeeper and on and on and on. Have a look: https://pypi.python.org/pypi?%3Aaction=search&term=twisted&s...

And then there's multiple ones of each to choose from. Look at amqp or reddis. There's something like four implementations of each. Even something like requests, theres treq, rxrequests, requests-twisted. Which one should I use?

And then there's Python 3. Only half of twisted works on Python 3. Which half? I guess one finds out when they give it a go.