PropertyValueSource has a rating of 2.0 stars from 1 review, indicating that most customers are generally dissatisfied with their purchases. PropertyValueSource ranks 1323rd among Real Estate sites.
The report they compile is fairly accurate and detailed. However, be aware that they will state that the report is $1.29, however after you accept their >1000 word user agreement, don't create a password or that authorizes them to bill you an $18.95 membership fee. To their credit, they did refund it immediately when I called. Which just indicates to me that this is their business model, since they didn't even blink when I complained.