ALSO, the best part about going with a YTCA breeder is that you'll know the full pedigree of your pup. That's probably the closest you'll come to a good health guaranty (no matter what a breeder promises on paper.) While I realize there are no guaranties with any living thing, I like to hedge my bets.
Both Jack and Tom were able to detail the lines they established for me so I know exactly where their pups came from. They have very healthy yorkies.
Good luck.
Tracey