When representing a buyer on REO properties, always make sure you read the bank addendum that is generated with an offer acceptance AT LEAST 3 TIMES.
There are terms and conditions in there that can be very costly to your buyers if you overlook them.
Most common are per diem charges, which are basically late charges averaging about $100 per day that your buyer will pay for each day the escrow closes late. The funny thing is the delays can actually be on the listing side, so you need to stay on top of things and GET IT IN WRITING that the buyer will not pay per diem charges if the delays are caused by the seller.
Also look for what things the bank will or will not pay for such as termite inspection, retrofitting, geological reports, etc. Each bank varies from one to the next in the approach they take to the sale, so double check this also.
A WORD OF ADVICE - no matter how bumpy the escrow gets and how much you feel the listing agent is slacking, remember to be EVERYONE'S BEST FRIEND during the transaction. You never know what other properties the listing agent has available, and you always was to be on good terms.