Chinese sites:
soufun.com has really edged out other sites, I think. Good search, good level of information including recent rents and management fees. You can report the agents if they post fake pictures. (Though some obvs still do.)
ganji.com and 58.com are also ok and have lots of by-owner. Koubei used to be, too, but they seem to be part of taobao now and I’ve used soufun.com for the past few moves
Good practice to confirm your requirements with the agent before going to EVERY apartment. They do seem to have an incentive just to show places, so will walk around with you even if they don’t have anything that you’d take. Just refuse to go to the apartment if they don’t confirm the wooden floor first. You will still run into problems (oops, I misunderstood/made a mistake) but far less.