Hi Andy
I've been using stomp.py in local development mode quite happily for the last 6 months. I don't use darwin, however connect to several TD & TRUST feeds. A minor niggle has been that auto restart doesn't work on a Mac (I have a system healthcheck and restart the container after 30s inactivity), however this should be resolved as I'm moving to an Ubuntu server
I looked at the NR example code but have diverged from it a bit, I think I've referred more to the author's (Jason Briggs) github pages
Have you tried debugging with a couple of breakpoints, eg in the connect_and_subscribe function ?
Steve