When I contacted the insurance companies before I chose one, I asked each one to send me a copy of their contract. Only one refused, so I of course immediately decided that company was not for me. I read all the others - specifically heredity, pre- existing conditions etc.
My feeling is if they won't provide you with the contract I would not fool or trust them. The one who would not give me a contract wanted me to sign up first - like I was going to sign on to something I has not read
I chose Healthy Paws, but I think from reading previous pet insurance posts that Pet Plan and Trupanion are petty popular.
I'm sure others will come on and give their version of choices.
I had a dog that had a neuro problem about 8 years ago that cost me $6000 so decided on a saving account and insurance.