I did a lot of research on pet insurance when I first got my rescue and decided to go with Pets Best. They have been VERY fast to pay claims (within 5 days or less), explain my benefits well, and have answered any and all questions I call about. They even covered a dermatology specialist's visit and testing which is not cheap!
In fact, I accidentally called the wrong pet insurance after Googling "Pets Best" to get the number - It started with "Pet" so I hit call. It took FOREVER to get in touch with a person, they were very short with me, and it wasn't until they couldn't find my policy that I realized I called the wrong place. Whew! Finally found the right number it was a very different experience. Pets Best answered right away and got my questions addressed.
They have an online chat service that has also been great and convenient.
Overall, I highly recommend. It has been very much worth the money.