personally, i wouldnt put much faith in a breeder with a 10 year guarantee - its simply something they cannot enforce. look closely at their guarantee - it states in most places if the dog isnt (something -- sweet, long lived, healthy, etc) - you get a replacement pup.
if your dog has a poor temperament, poor health, etc - do you want it replaced from the same breeder that gave you the LAST bad animal?
in addition, to get the replacement you need to give BACk the other dog - do you think after having a dog for 3-4 years (or longer), if something goes wrong you want to give it away for a new one?
if you dont do what she wants in terms of vaccines, other preventative care, kenneling, and feeding she can void the agreement.
seems to me its a paper that sounds good at first glance, and then later has a lot of loopholes and stuff you dont want to deal with.
personally, id want more health testing, more titling, more proof of being structurally correct. no one can guarantee me that a dog will live 10 years - but you can do your best to make sure they are healthy and what the breed SHOULD be.