Comparable sale is a similar model match sale that would support or justify the value of your subject property.
Competitive property, I think you may have been referring to comparable listings which is the same as a comparable sale except that it has not sold yet. When we prepare a BPO (Broker Price Opinion) for the bank they ask us to provide 3-4 comparable listings, (active) and 3-4 comparable sales for the subject. The purpose is to see what has recently sold and what is currently available which will help the bank understand the current market in that area. The key is knowing and identifying a declining market which will require you to price your home very aggressively to ensure it sells. If your in a declining market and your property is priced above current comps it will never sell.
Most banks or reo companies are never in the city they are selling the property and they require local agents to be their eyes in the field and tell them what the current market trends are.