Let me share a recent experience.
I was talking with a noteholder who sold his home one month prior and had just received his first payment. The home sold for $559,000.
I looked at the property online. It was beautiful. I checked three different sites to get some idea as to the current market value, seeking confirmation of the sales price. The values were $579,000-$569,000 and $645,000. So, initially, I had comfort that the current value was equal to or higher than the sales price, which is what note buyers are looking for.
However, with the closing just 30 days in the past, I would have expected all three sites to be fairly consistent. But, one of them was way out of whack.
These sites are a tool for sellers, buyers, investors and note buyers to use in gathering information. They are not definitive values with which to base any decision making on. Hiring a real estate agent and allowing that person to do an analysis of neighborhood comparable values, recent sales, etc. is the correct and professional way to get an accurate current market value of a home.