My take on these warranties is that by purchasing one I've already been out a couple thou in repairs on a car, trailer, boat I haven't left the dealership with yet. Also, by not buying them on a dozen cars and trucks and a handful of boats, quads, etc., I'm ahead tens of thousands of dollars. I have never had a major problem but twice that I recall, and that was a transmission in an SUV and an engine in an Oldsmobile, both replaced in the original warranty.
Disclaimer: I always buy them for vacuums because they all seem junk these days.
'11 Eagle 320RLDS
'02 F350 PSD Dually 4WD
DW's Ride, '13 Expedition