Best for what purpose? Bite sport, LE, military, SAR, show, OB, herding...
The dog must fit the handler and the home. The best breeder and dog for me is going to be very different than the best dog and breeder for you. It happens sometimes that in the quest for the best dog, a handler will end up with too much dog. This is a dog that requires a lot of experience and time to train and form a bond of mutual respect, or a partnership. Lacking purpose, direction and motivation, these dogs can be very undisciplined and destructive. My favorite dog was HA, DA and crate aggressive when I got her. Most people wouldn't go near her kennel, let alone get her out.
The best breeder is the one that breeds dogs with the working or show criteria you are seeking, meets all health screening requirements, provides proper husbandry for their dogs, evaluates the litter and prospective buyers, and places the right dogs with the right owners.
You first need to understand what you want in a dog. Words like stable, loyal, intelligent, are not descriptive enough. You need to understand thresholds, drive, aggression, biddability, basically the personality traits that make up temperament. You can't gain this knowledge without working with dogs. This takes real world experience with a number of dogs. No one is borne with this knowledge. We all start with our first dog and our experience and knowledge grows from there.
I suggest you start with the dog you have and get involved in some type of sport where you can experience many other dogs and personality types. Welcome to the world of dogs, where nothing happens in a hurry and rarely when you want it to.
When a dog saves the life of a man, it becomes clear that partnership knows no bounds.
Fama - T.E.D.D. OEF XI-XII (GSD)(RET)
Marshall - T.E.D.D. OEF XII-XIII (Lab)(SF EDD)
Lucian - Med Alert / Mobility SD (Cane Corso)
Pud - the old man (Pit x Lab)