We've had a few major claims including one for over $3,000 and one that happened out of country. We've never had a problem with them paying anything we were entitled too. When one of our dogs died due to an accident they paid to have him euthanized, part of his cremation costs and even paid us the $800 we paid for our dog (which in truth felt a little weird and we made a donation in his name with the money).
Yes, when one of our dogs had a very expensive year, they did reduce our co-pay to 60% but the next year they put it back up to 80% without us every asking. When I was looking for insurance, two things were very important to me. 1. They would not cancel my pet's insurance regardless of the number of claims. 2. My monthly premiums would not increase because of claims. They were the only insurance company that had these two features. I completely understood increasing our co-pay and at least this was something that was in my control since I knew what to expect. But canceling my pets or raising the premiums was too risky for me.
We just got another dog and did shop around to see what else is out there but still found PC to be the best for us.