Good post Longblades. Yes a health guarantee is important, you mentioned too about spay and neuter. I used two breeders and since I had a male and female it was important to spay the female at a reasonable age, the breeder of the male wanted me to neuter him at six months but I refused. He will be neutered after one year.
I have a very easy and ongoing relationship with both of the breeders, but the breeder of the female is much more open. So if you can converse with your breeder up front it may be a good sign. Also, try to go to their kennels for a visit and see first hand what their set up is. It will tell you a lot.
Also, both of my breeders have a return policy. If for any reason I cannot or choose not to keep these dogs I am legally bound to return them to the breeder. They take full responsibility for these pups from birth to death.