Well, it's obvious that a particular person has an agenda here to promote Collier Ranch. To anyone looking at Collier Ranch, I highly suggest you take a look at the way they respond to people that did not have a good experience with them.
Collier Ranch Yorkies - Sunnyvale, CA
While there are several good reviews on Yelp, it's interesting to note that they came after the start of a particular FB page and after several of the posters on that page said they had joined there because their breeders asked them to. ***NOTE*** I'm not saying that Collier Ranch or anyone else asked some of their posters to go put up reviews defending the breeder.
One of the things to look at in a breeder is how they handle problems with their dogs and their customers. Between their response on Yelp as well as some of their statements on FB, you've got a pretty good idea of how things are handled. What a potential buyer decides to do with that information is up to them.