Services like this concern me because I don't know the credibility of the person on the other end, nor do I know if the effort I put into someone else's review is going to guarantee that I get an equally verbose one. In the same vein, the function of a site defines the design and someone telling me that my content portal "is way too busy" isn't going to help me when I wasn't going for some sort of minimalistic trend the reviewer may be more likely to rate higher.

I'm not sure if you're changing things right now or A/B testing, but when I initially went to your link there were examples of what I could expect. Now there's no way of knowing what the process looks like and how these viewers see my site. Is it a screengrab of the homepage, do they get the link and surf around?

Also, is there anything stopping someone from writing a bunch of useless one-liner reviews just to get their site seen?