Sales data can be misleading in a market like Huntsville. Our MLS covers more than 13 counties and overlaps other MLS's in other counties, up to and including Tennessee.
Additionally, sales data can be misleading from neighborhood to neighborhood, and this holds true for most markets. For example, we have areas within a 1/2 mile radius where property values can vary from $50,000 to $500,000.
Finally, I do all my comp reports based on the goals of my clients. For the best approximation of value, you need to find an agent who will compare apples to apples and oranges to oranges. Appraisers typically don't compare the foreclosure that sold down the street at 30% below market value to a home which the owner is selling at market value....and neither should your agent.