We have used PetPlan for several years now with three of our dogs. Highly recommend pet owners to have insurance, you do not want to have to face an emergency without one.
And their customer service is very good, recently I was assisted by Emily B. regarding a year old vet bill that I had failed to file and she was great, she helped me get the re-reimbursement promptly and was very good following up with updates.
And regarding PetPlan, do your homework, but my experience has been great. Used them with two of my dogs that have passed and I am using them with my current dog. I read all the small print and w/ my previous dogs they covered what they said they would, including a very expensive emergency surgery, over $10k, trying to save my last dog.