You have received very informative answers thus far. At the present time, I have a working relationship with a Seller's Broker, in order to represent the buyer, with their short sale property in the upper east side of Manhattan; so I speak from a point of real-world experience on this topic. I want to add something and emphasize a point that most apartment buyers don't seem to realize when apartment hunting. This info can wind up saving you a significant amount of money, and in the case of a short sale, time...
When you look at apartments that are on the market, and advertised as short sale opportunities, you really have to have your "comparable" homework done. The prices of apartments in a particular building, and neighborhood, will vary greatly. If you find a short sale situation, by way of the Internet in the form of ads placed by the owner, Real Estate Broker or bank, they will do very little, if anything, in order to help you discover the true value of the property. You therefore need to protect yourself by having your own representation, in the form of a Buyer's Agent. Just keep in mind that there is no cost to you associated with having your own Buyer's Agent, because the seller pays the entire commission.
Senior Real Estate Sale Associate