Hassle-free home valuation website

We're trying to get rid of our PMI, and an appraiser from the insurance company will come to check out our house once some minor updates are completed (six new windows and a new storm door). I'm really curious about what he'll have to say. I wanted to have a rough idea before he arrived, and finally found an internet home appraisal site that doesn't send my information to a real estate agent (or agents). It costs $5, but I'd rather have that than a bunch of realtors banging down my door.

The site, Smart Home Buy, seems to be geared towards people who are shopping rather than selling--the report also lists things like crime rates, public and private school information, and hazardous-waste sites.

Of course, I have no idea how accurate it is; however, if the appraiser gives me a vastly different figure, I suppose I'll start asking some questions!