It may be a good idea before buying travel insurance to check with your employer to see if you are covered for medical problems / evacuation. My company covers all out of province/country emergency medical problems and medical evacutaion, thus I never buy the cruise insurance.
I am willing to risk the loss of the cruise price if I miss the ship, as this is less than half the cost of my vacation. I can always change my flights and use them at anytime within a year, and most pre-cruise hotel rooms give a 24/48 hr cancellation policy, so my risk is only the cruise. If my employer did not supply the medical benifit, I would definitly buy this coverage.