I used to have petplan. They raised the prices and i've got a pretty healthy dog, so i just ended up dropping it. I think it was costing me around $600 per year (with 20% copay and $8k max per incident per year). At those prices, I figured I might as well take my chances and just pay as needed.
When I did have to use it, which was hardly ever, I didn't have any complaints. I was paid back within a few weeks and customer service was good. It's not cheap though, but insurance never is for anything.