Home Warranty companies

A friend of mine was telling me how his Home Warranty helped him pay
for a new AC unit. So I started looking into adding such a warranty
to my house. In researching companies on the web it seems that almost
all of them have dozens and dozens of complaints and reports of them
refusing to pay for repairs because of the "lack of maintenance
records", esp for any big dollar items like AC. I got "on line"
quotes from a couple of them and literally within a minute or two of
my hitting the enter key with my info my phone was ringing.

Anyone on here have any experiences? .. either as a user or doing work
for them?