I just bought one from Toyota for my new Sienna. With power sliding doors and tailgate and all other manner of gadgets, gizmos and computers, it made sense ONLY after getting to the bottom of dealer pricing on these things. The Internet is your friend! Make sure you don't over pay.
With the Toyota plans, you can buy them from any dealer. There are a few who sell them online near cost because Toyota pays a bonus if a certain number are sold each month. I wanted a 8 yr/100,000 plan. The dealer where I bought the van offered it for $1800. I told him I was an internet shopper and had received some strongly discounted offers (but didn't give away the number). He immediately came down to his "employee price" of $1240 which he said was the lowest he could go. I bought the exact same merchandise from a Toyota dealer in the state next door for $1040. At that price, an extra 5 years and 65,000 miles coverage seemed like a pretty good bet. It's in the computer and good for service at over 1500 Toyota dealers in US and Canada. We plan on traveling extensively in this car so it just seemed to fit our plans.
Also, another great feature of this plan is it is refundable on a prorated basis with a $25 admin fee so that makes it virtually risk free in my mind.