I think I would be less likely to go to a breeder that uses ENS. It's crap science at best.
That said - it depends. Buying a near grown dog or buying a puppy. am I after a green dog or a dog with some training? What do I want out of this dog usually plays into where I buy it from more so than the extra trimmings.
My breed is number 35ish on the popularity scale. Finding a breeder who health tests, has a sane contract, and actually selects for temperament is hard enough. I don't think I could add a whole lot on there and actually find someone.