Do you have some links with information about kqueue being broken? I know that the python integration doesn't work well. We started using polling on OS X instead of watchdog's kqueue driver.
kqueue()'s support of process monitoring on OS X doesn't allow for tracking of new processes that are created, and automatically attaching to them.
There are also differences that make it more difficult to port various kqueue() features from one platform to another. I'm not sure how much of a difference that makes to you.
The documentation on OS X is also lacking, for example EVFILT_USER is supported on Darwin/XNU but it is not documented in the man page for kqueue.
http://pypi.python.org/pypi/watchdog