I'm not a fan of them. I bought my first one in almost 10 years on the Audi I purchased, only because I'm not familiar with them yet to work on it myself with confidence. It was a top tier warranty offered by the MB dealer where I purchased the car.
Last year I needed to use it. And while they did pay, they only paid about half of the repair bill and that was after both the dealership and I both called the warranty company and argued with them about an item called an oil valley gasket that the warranty company claims isn't covered by their "all engine seals and gaskets"
Before the warranty is up I will be taking it again because the suspension bushings are shot, another item the paperwork lists as a covered item. I fully expect them to attempt to weasel out of paying on that bill as well.
Prior to that I had another warranty on a Cadillac STS that barely paid for itself, again with a few trips to the dealership and arguments about what they covered.
On my current STS and Escalade I did not buy an extended warranty. I'd rather take the chance that I'll have to drop $5K on and engine or transmission myself than worry about what they'll want to pay for.