I am with AXA, and although they sometimes take their time with payments, I have found them to be very good. They were the only insurance company that didn't have a list of exclusions for Benji due to his FIV status, but go on what the vet says instead (I think petplan e-mailed me a list of everything excluded and it was shocking how much they wouldn't cover! including allergies, stomach problems and cancer???)
Benji has an excess of 50, the kittens are 75 each but I don't have to pay a percentage of the cost. They have also e-mailed me a blank claim pdf form now, instead of having to wait for one in the post, which is very useful, as both Ginger and Benji are claiming lots at the moment.