What are your opinions on breeding goats-milk or meet production?

ok, first of all I live on a hill farm in Wales, and I'd like to buy goats and breed them, has anyone ever breed goats? what are the advantage and disadvantage of keeping them? since Iive on a hill farm, and most of our boundaries are dry stone walls, will these be more of a problem than sheep? and most importantly do they pay good for milk production or even meet production in the UK? compared to other livestock..