While I haven't had a chance to use 3.5's async/await syntax, I have used AsyncIO pretty heavily to deal with multiple sensor inputs/outputs on a Raspberry Pi.

The author is right. If you write a coroutine, any code that uses it must also be a coroutine. This is pretty annoying when you're trying to test something manually. It bubbles up this way until you eventually hit the event loop.

If you're trying to debug a coroutine in the interactive shell you've got to do something like this:

  loop = asyncio.get_event_loop()
  # Blocking call which returns when the hello_world() coroutine is done
  loop.run_until_complete(hello_world())
  loop.close()

That's my main beef with it. Debugging can also be painful because when you hit an exception, your stack trace will also involve the asyncio library. Aside from those complaints, I'm a fan. It works fine and reads better than callback-style code.