Theoneandonly - we have PetPlan insurance for our two dogs and for the cat, and I would highly recommend it.
Ddog2 had three knee operations last year - she ruptured the cruciate ligaments in both knees, so had operations on both of those, one after the other, then, just as she was getting back to a normal level of activity and stamina, she dislocated a kneecap and needed a third operation. She also developed a gastric ulcer, due to the anti-inflammatories she was given for the dislocation.
All this meant over a year of visits to the vet hospital, inpatient stays, medication, consultations - and the bill came to over £10,000 in total. PetPlan have paid up without a murmur, and have paid the vet hospital directly, rather than us having to pay the bill and claim it back. Not all vets will do this, but I suspect the bigger practices, and specialist vet hospitals will - and it certainly made life easier for us.
We've also had the renewal quote for her insurance, and we feared it would go up dramatically, but it actually hasn't gone up hugely.
Over the years, we've had PetPlan insurance for all our pets - four cats and two dogs - and between them they have had a number of vet visits, and we've never had a problem with getting payment from PetPlan.