I'm glad to hear you're testing this first. It's always best to make sure an idea will work before you jump in...
Have you checked out sites that conduct surveys? They'd probably be more than happy to conduct the survey for you and they already have folks willing to particpate.
Is your site going to be subscription-based like Consumer Reports? Since they don't use outside advertising that would bias their reports, it gives them credibility.
I just discovered this site --
http://www.blagger.com/ -- and appreciate the feedback posted on it.
Diane
The business writer who helps people grow their small business
http://www.BouncePublishing.com