@40andlovelife - I think the main difference between a breeder (i.e. someone who owns generations of the dog) vs. a family (Bob down the road just breeding for fun or because their dog is 'nice') is that family types are far more of a risk when you buy from them.
'Breeders' will almost certainly be able to devote more time, energy and resources into ensuring the puppies are raised appropriately (raising a puppy well from 0-8 weeks is bloody hard and involves far more than socialising them with a few kids and the hoover), come from the healthiest lines (they should have spent months finding the best stud, for example), and also will be able to guide you to an appropriate puppy in the litter because they know the breed so well.
The main risk you take buying from a family is that they almost certainly won't have used the healthiest stud or bitch to breed from. That isn't because they don't care, but rather because they just think breeding is easy and it's easy to find a stud- and there's a lot that goes on behind the scenes when you're trying to breed a health animal. Because of their lack of care over finding the right stud that means higher chances of dysplasia, heart conditions, eye issues etc.
For example, there's a very popular stud that I have used for one of my litters - and his owner doesn't breed him with bitches that aren't KC registered or from good lines. They have a set of hip scores, for example, and if the bitches hip scores are too high they absolutely will not let their dog be used as a stud. That is because using a good stud on a 'weaker' bitch (i.e. one that isn't healthy, or Bobs dog down the road i.e. the family pet) not only makes the breed worse off - and good breeders care about the breed as well as their own dog - it also ultimately devalues the stud.
What I will say, is I am a breeder (Goldies - so I do have a vested interested in seeing people buy healthy puppies). And I see a lot of Goldie litters come up near me all the time - be that Pets4Homes, KC, ChampDogs, and rarely do I look at a litter and think 'Yes, I'd buy from that family' and very very often, the people I flinch away from most are 'family' breeders because the dogs health tests are abysmal (if they are done at all).
This link: https://www.dogbreedhealth.com/boxer/ gives you a breakdown of the test you should want to see.
Ultimately, you should want to buy the puppy that comes from the parents with the best health tests because that means your puppy has had the best possible start to life - and, hopefully, will live a long and happy life. Finding the right breeder is really hard, and can take months or even a year+ but ultimately it's worth it for the peace of mind that comes from buying a puppy and knowing that a horribly health condition, or life-limiting condition, isn't right around the corner.