As far as I know it's PDA all the way. They will go to war with you if need be, the NPA will never take your side in a dispute with employers, so insurance with them is probably as useful as a chocolate teapot.
I would go for the PDA for the insurance, and to the members of this forum for emotional support if it were needed.
I think it is important to recognise that the PDA will stick up for you, and advise you, they are very good at that, but your hand will not be held continuously and hugs will not be given all the time. That is what friends are for.