Whats everyones opinions on this?

If you just bred best to best are you always going to get hybrid vigour?

I been told first cross makes best battle dogs?

I been getting help off a fella to get started but once you look at his peds they all scatter bred dogs everything i read makes me dodge scatter breeding.
I am no breeder just interested on thoughts and experiances.
From what i see scatter bred will battle but not produce and if thats right why has this fella been breeding that way for 20 years??