If you are having good prelabour signs, I'd do it.
I had mine during labour, so it really kicked things along for me, but I'm definitly opting for at least one of these if I go overdue this time.
I have heard what Kelly said as well though about any sort of induction adn VBAC too. Hmmm - not sure. I guess they wouldn't offer if they didn't think it was safe for you?