I generally stick with the tried and true wisdom that the actuaries who price the warranties are better at predicting the probability of claims than me, so I am better off self-insuring.

That said, coverage for major repairs until the car is 8 years old or has 100k+ miles sounds enticing. But I'd want to know:

• It says "coverage begins at the time of purchase," but does that actually mean you get 6 years/72k miles from when coverage begins, or just that coverage begins at time of purchase and ends when the car is 6 years old or has 72k on the odometer? Maybe the answer to that is obvious (I've never researched used car warranties), but it's not clear to me.
• Who is actually backing the warranty? Hertz? Some third party? There is no name on the PDF.
• Why does the first page of the PDF have coverages called Prestige, Premium, Standard and Compact, while the other pages refer to Powertrain, Silver, Gold and Gold Plus? Are these actually the same thing?
• Are TPMS sensors covered? I don't see it mentioned in a quick skim.

FWIW in 2012 we bought a 2010 Mazda 5 with about 36k miles from Rent2Buy, and 4 years and about 20k miles later (we only drive on weekends) we've had no major mechanical issues. We've replaced one tire, two TPMS sensors, four brake pads and an emissions sensor, but I don't think any of those things would have been covered by this warranty.