Peter, there's some interesting reading on
Denver's BBB site. Looks like they got into the business by acquiring Prizm (Prizm Administrative Solutions/Prizm Group).
Not sure how good they are, but having followed max49's issues I'm not sure I'd get an extended warranty even for an Essex.
One thing to ask for - is the policy exclusionary, i.e. lists things they do not cover. My understanding from reading other posts on iRV2.com is you should get this type, not the type that only lists things it covers.
Stewart