Well to be honest, I learned about this yesterday.
I found a bug in Piston and after I opened an issue about it, I got this reply:

https://github.com/steemit/steem-python

That's good news, because I became worried, that there were no updates in Piston for the last 3 months.

After:

• piston
• steem-py
• piston-lib

We now have

• steem-python

... and it's official !

I will port my scripts over today and see, how that works out.
I had some issues with piston-lib and maybe updating will help.

http://steem.readthedocs.io/en/latest/

There aren't many examples yet and maybe I can post some on my blog.
I will post some more about my experience under #steem-python.

If you have any ideas for a script, let me know in the comments.