Pet Plan charges me £480 per year for a 11 year old springer with a significant history of vets bills (Many thousands of pounds). I have never had any trouble with claims. Vet claims direct to Pet Plan, All I do is sign the claim form. I have a limit on the policy of £4k per year.
Halifax recently cancelled all pet insurance policy's leaving owners with a problem as new policies with other insurers will not cover existing conditions.
Just like everything else you have to balance cost against service. It's all very well getting the cheapest on the market if it gives a decent service but many don't. Do you have to pay and claim or can your vet tie into the scheme? Does your plan cover every eventuality with no cover cap or does it only allow for a set amount? If you have to pay and claim how long do you have to wait for reimbursement?
The cheapest is not always the best so make sure you weigh all the odds before you buy.