Directly to your question, mine is with EZ Care and I have nothing but good things to say about them. Nearly every time I've taken the coach to a shop or had someone come to my site for repair, the vendor has readily agreed to work with them directly both on authorization AND payment so my only cost was the $50 deductible. A couple of these vendors have commented to me that they love working with EZ Care because the are easy to do business with.
Good advice from Dickson. I'd point out that ALL businesses are in business to make money so don't hold that against extended warranty companies. Do your research... both of companies and their offerings... but also of what your own expectations are.
If you want to feel reasonably assured that you can predict your RV maintenance cost and are OK with paying for the "insurance"... you may well be happy with an extended warranty. On the other hand, if at the end of the extended warranty period you'll feel like you've been had if your claims didn't add up to your premiums you should think seriously about self-insuring.
For us, as newbies with a new DP, the peace of mind was important and we're happy with it. Sorry if I answered a question you didn't ask...
Best of luck...