I've used this briefly just for some quick little searches. It's a great handy little tool. The only drawback is that it is the median of the ASKING prices for rents on properties, not necessarily what they actually rent for. I'd assume they still give a pretty good idea of the area though.
That's an awesome tool. I did a quick check of some of my properties, and the only qualm I have is that the search radius is a little wide. It showed one of my properties being about $150 less per month than average, but when I checked properties in the same subdivision and a subdivision right next door, it was actually about $50 higher than average. Still, it's a nice tool.