You might want to check them out on the internet and BBB. But last year I needed a plumber and called the company that I had used for several years and was asked if I was a member of their plan? No, didn't know what they were talking about. But it turned out if I was a member they would be able to come out immediately, if not, I would have to wait about a week. I thanked them, hung up and found another plumber. The guy that came out said it was becoming a new thing, he was picking up all the business these other places were losing, so he was happy.
We had a service contract for the first 10 years on our heater, then the company went out of business and I never found another one.