It isn't often in real estate transactions that virtually all parties with a financial interest can be winners in the same transaction. A successful Short Sale is one of those rare situations where everyone wins.
The Buyer Wins by acquiring a property at below market price. While some Short Sales will be bigger bargains than others, nearly all Short Sales will represent a good deal for the buyer.
The Seller Wins by avoiding foreclosure and all the credit damage that goes along with it. The property gets sold, all the loans get paid off and the existing lender pays all the sales costs. In most cases the Seller has no out-of-pocket expenses.
The Mortgage Holder Wins by reducing the loss they absorb to get the delinquent loan off their books. Mortgage companies know that the costs associated with acquiring a property through foreclosure hit their bottom line - hard. To resell the property the mortgage company frequently needs to invest money in clean up and repairs, and they need to pay staff to manage and maintain the property as well. This is precisely why they have set up Loss Mitigation Departments to resolve delinquent mortgages before the foreclosure is complete.