I have heard a lot of things on this subject. But I never seen a good article saying it's good. Every article I seen saying it's good only use buzzwords, few

I have heard a lot of things on this subject. But I never seen a good article saying it's good. Every article I seen saying it's good only use buzzwords, few numbers, but never tell real life numbers, like how many people worked there, how many they produced, how much they sold it, etc...