Maybe we have bad Priceline luck but this has happened to us twice... we had a priceline reservation at a hotel that closed (once at the Hyatt in Orlando and once in Chicago)....both times they gave us the option of refunding our $$ or moving us to another hotel. In Orlando I did not want the hotel they offered so I took the refund and rebid (got a better property anyways!!) and in Chicago they offered a hotel in a better location for us anyways so we just took the new placement.
Both times they emaile us to call customer service and it wasn't too big of a hassle...they were pretty nice both times. I figure you can't lose....worst case scenario, you don't like their replacement and you have to start over.
BTW, often when properties file for bankruptcy they will continue to operate, so you might be OK anyways.