Having EAD will make a huge difference compared to H-1B visa especially for those who get their degree from CN or EU.
Also EAD means that the holder does not need sponsor, which is prefered by almost all kinds of companies.
I don't where you get this idea from: "高校和大公司是不愁H1B名額的,中小公司可能有優勢." Even some ivy league schools and UC systems don't generally sponsor H-1B but J-1 instead.