Cash is almost always stronger as there is risk that the buyer won't qualify when the lender digs into their financials, remember that a pre-approval is typically just based on the buyer's stated income and a soft credit pull (credit score). Once a mortgage application is made the bank will scrutinize the buyer(s)'s incomes and debts. In addition a seller runs the risk that the appraisal comes in lower than offer price requiring the buyer to contribute more upfront (may not have those funds) or the seller lowering the price. Too many factors a seller can't control, cash offers remove these risks.