Line breeding is the best way forward to maintain breeding ........particularly if you are establishing a herd. Within 3/4 generations, you should be able to breed a predictable type.i.e Excellent udder/topline/body/ etc
If you outcross then basically you will never know what the outcome will be.............the genes are in a tumbler of possibility and you could just as easily end up with mish mash.
In 40 years I have only outcrossed once.......that was importing goats due government mismanagement of the scrapie scheme.
I will at some point, mate father to daughter/mother to son. My Saanens are so alike I have to eartag asap after birth so I know wh is who !!!!!
I do the same with my Nubians as well...............can trace all my pedigrees in direct descent to 1922.
I have animals with correct type/udder & milk yield.
You do need to understand how the system works though. If you are mating just to get kids then of course it does not matter how you do it.