Depending on factors such as the particular financial institutions foreclosure processes, foreclosures are easier to close. For either a Foreclosure of a Short Sale, you typically get a great price but, you assume the risk that the home won't close and the deal can be pulled at anytime (even up to closing day). Clear title may be an other issue depending on how it's offerred. With eith you can have multiple offers.
Foreclosures, present only 2 parties during the decision process. The bank has does have incentive to sell. For these reasons forclosures may be easier.
Short sales, have 3 parties (seller, bank, and the buyer). More parties, less fun. What happens in Short Sale is that the the bank and the seller enter into an agreement to sell the home at a lower price to prevent a foreclosure. However, the bank will want to try and recoup their loss. If at anytime they feel they can get a better price, they will pull the deal.
If you have patience and strong constitution you can try either of these buying methods, but I do recommend hiring a Buyers Agent to help smooth process and handle most of the detail.
Hope this helps you understand a little more.