Those aftermarket warranties sold by dealers usually aren't too bad, but those offered by stand alone companies (US Fidelis, Mogi, etc) are useless nightmares. They operate only to make a profit, and usually the claims process is very very painful. I'd advise STRONGLY against them. Car and Driver (I think) had an article not too long ago where they compared these companies, and I remember the results being pretty comical. Comedy is not a good thing when you're trying to get your warranty company to pay up on a claim.