If you are considering buying an extended warranty, here are a few thoughts/tips:
1. Get the Infiniti warranty. Third party companies are like health insurance companies, they review every claim and I've heard of many cases where they've denied coverage for things. Additionally, I've also heard of many of them going out of business so you'd be SOL if you had a claim.
2. Shop around for the warranty. If today is like a few years ago, you'll see about a 100% markup on the costs of extended warranties. They are BIG moneymakers for dealers. There are Infiniti dealers around the country who will heavily discount the warranties. If anyone has any experience with a specific dealership and would be willing to post that would be appreciated. I can't remember who the specific dealers were when I looked a couple of years ago. You are not required to buy the warranty from the dealer where you bought the car so don't be afraid to call around.
3. Negotiate the price! Again, there is about a 100% markup on extended warranties so if you don't want to shop around, have a frank conversation with your dealer. Tell them something of something is better than all of nothing if they want to sell the warranty. If I'm remembering correctly, I had negotiated a split of their markup (let them keep a 50% markup and I got quite few hundred off the price) on one warranty when I was considering a lease buyout.
4. Look closely at the deductible options. You are basically buying insurance. The goal is to have coverage in case something major happens. If there are 4 or 5 relatively minor fixes you need over the life of your car, it will probably come close to the cost of the warranty so hindsight would say you probably shouldn't have purchased it. Most people are considering the warranty for big ticket items that would really affect their wallet. If that's the case, I would consider a much higher deductible to get a lower cost warranty. True, you'll have to pay for some repairs but again, you are insuring the big ticket items which should have a low repair rate but would be covered. It's just paying less for the insurance since the potential of a claim is lower. Of course some people have the money and just want piece of mind and that's why the $0 deductibles are offered - and are more expensive.
Hope that helps some folks!