I know that we should never leave a choker-type collar on a dog when they
are unsupervised, because they could get caught on something and be
strangled to death.  Does anyone have any other info on whether chokers are
good or bad?  How about the pinch-type or prong collars?

I don't recommend chokers since it will hurt their neck. It needs to be something that can be attached to their chest on top of the neck for better support.