It's indeed better.
Now with when running my previous script I can see the exception ;-)

Exception in thread Thread-2:
Traceback (most recent call last):
  File "C:\dev\python\trunk1\lib\threading.py", line 523, in
__bootstrap_inner
    self.run()
  File "C:\dev\python\trunk1\lib\threading.py", line 478, in run
    self.__target(*self.__args, **self.__kwargs)
  File "<stdin>", line 3, in f
  File "C:\dev\python\trunk1\lib\io.py", line 1473, in write
    self.buffer.write(b)
  File "C:\dev\python\trunk1\lib\io.py", line 1041, in write
    self._write_buf.extend(b)
BufferError: Existing exports of data: object cannot be re-sized

Again, I think this is unfortunate for a simple script that prints from
several threads.