We have a one-night stay in San Diego next week (Jul 31). We'd like to stay at either the SD Marriott Marquis Marina, Coronado Island, or Gaslamp Quarter. Prices are $329-$485 for these properties. (although I just found a MR-exclusive rate on Coronado for $280 which I'm holding - so that's the rate to beat at any of these properties).

Can someone please PM me with any useful comparison sites for these properties?