Zhejiang University is the whole academic story here, and it is a large one: comprehensive, consistently in the top tier for engineering, computer science, agriculture and medicine, and a major host for government scholarship students. Because there is effectively one destination, the decision is simpler than in Beijing or Shanghai — if Zhejiang covers your subject, the city question is already answered.
The city itself is smaller than Shanghai and easier to live in. Commutes are shorter, the metro is clean, and the cost base is a third lower. Alibaba, NetEase and the e-commerce ecosystem they spawned give the city a commercial personality that is unusually accessible to graduates who want to stay.