I am at Zürich. Just try to answer some of your question:
住哪兒較好: It is really fully depend on you. Some likes inside the city, someone not. My feeling is: within Switzerland it is almost same for everywhere. The public transports are very handy.
孩子讀書不會德語怎麽辦: donot worry, they learn very fast. And in the schools they have the extra German course for your kids for free.
中國人在那兒容易適應: not really easy.If you come from China directly, even harder. A bit living experience in other EU city might help.It is really not easy to get Swiss friend.