I use tripadvisor.com to help choose the hotel and then asiarooms.com or cnet for booking- or direct to the hotel itself for a comparison rate.
I just checked into the Renaissance Shanghai YuYuan last night and am using their computer from the exec lounge. Gorgeous views of the huangpu river, incredible pool, great restaurant options, 100 yard walk to Yu Gardens (prime tourist location). Not so great for public transporation but taxis are cheap.