We feel like we can't afford not to have the extended warranties. We use CAE manikins. When something goes wrong, you call tech support, they help you diagnose the problem and then they will overnight the part to you for no charge if you have the warranty. It really has reduced our down time.
We accidentally allowed our extended warranty for our Gaumard Noelle to lapse and when she broke down, they helped diagnose the problem over the phone, but we would have had to pay to ship her back and pay for repairs, which was almost more than the manikin was worth.
Overall, I'm definitely a fan of extended warranties for high fidelity manikins.