AZ Who Is The Seller??
Since it's likely you already know whether you want to purchase a condo or single family home, we will focus on the identity of the Seller and what that means to you.
Bank Owned (Reo) Properties:
As the name implies this homes belongs to a bank and/or mortgage company and the Seller is the entity. It was acquired (redeemed) through the action of foreclosure. It will be sold in As-Is condition without warranty of any type. The Seller (bank) will not provide the Seller Property Disclosure Statement since the bank or mortgage company has no first hand knowledge of the property.
In a short sale, the Seller is a natural person who still retains their legal right of ownership. The home is not owned by a bank or mortgage company, though foreclosure may be imminent. The term "short sale" means the Seller is asking the lender to accept a price for the sale of the property "short" of the balance owed. The Seller will usually produce disclosure documents as required by law, but they are unlikely to address items in need of repair. The banks/mortgage company must agree to the sales price, along with the terms and conditions of the purchase contract for the sale to be completed. With the involvement of additional parties, a short sale can take many months to close escrow.
A traditional sale is one in which the Seller has full legal right and authority to sell their home without involvement of any party having a mortgage related interest. This Seller generally provides disclosure documents and has some willingness to perform repairs. They can usually close escrow and deliver the property to the Buyer in 30 days.
Of course there are other types of sales (lease purchase, probate, court approval, relo, auction, etc.,) but since their occurrence is infrequent, they are most easily explained on a case by case basis.