Mine are excellent. My last broody hatched 13 out of 14. I've had 100% hatches with broodies, but never with an incubator.
I have a nice Brinsea incubator, but a good broody hen will always be my first choice. The incubator was designed to mimic her natural abilities, so for best results, I choose a broody. I love that I don't have to worry about power outages, temp spikes or humidity levels and I don't need to provide a heat lamp for the babies that hatch - mama hen takes care of everything.